Home

Available in

Contents

1. It is inadvisable to use blink rates of 4Hz or greater since these may cause physiological discomfort including nausea and dizziness Adjacent blinking areas can also produce motion and metacontrast effects that might be distracting 5 2 8 Scrolling displays Scrolling is used when information is too large to fit onto one screen It usually requires sustained visual and manual interaction or in the case of a series of automatic sequentially scrolled displays numerous sustained glances Scrolling is therefore not suitable to use within the driving environment 5 2 9 Head up displays Head up displays HUD consist of a virtual image that is optically superimposed on the driver s forward field of view using either the windshield or a separate optical element The safety benefits of HUDs are generally small and in some instances HUDs produce poorer performance Gish and Staplin 1995 Therefore the following guidelines should be followed e do not present the HUD image in the driver s central field of view as it will mask external objects e drivers should be able to turn the HUD off e important HUD information should be coupled with an auditory alert 27 e while the HUD image must be visible in all potential viewing conditions luminance contrast requirements for HUDs are a concern because of the dynamic interference with the background road traffic environment e virtual image distances should be between 2 5 to 4 metres from dri
2. and thus the type of control will depend on the sort of information to be transmitted Controls that require fine control or adjustment for example a stylus or large forces are unsuitable for in vehicle systems that are used while driving as are controls that are designed for language or data entry such as keyboards Table 2 Selecting discrete controls Adams 2001 Type Use 1 Linear Push button For brief one touch activation of a function Slide Where two or more positions are required along a continuum to allow easy recognition of relative switch settings eg auditory levels across channels Toggle Where two positions typically on off left right are required or when space is severely restricted Rocker Where two positions are required and toggles may cause snagging problems or where limited panel space makes separate labelling of switch positions not possible Push pull Where two positions are required and such configuration is expected or where panel space is scarce and related functions can be combined eg ON OFF volume control Three position push pulls should only be used where inadvertent positioning is not critical 2 Rotary Selector Where three or more positions are required In two position applications where swift visual identification is more important than positioning speed Key operator In two position applications to prevent unauthorised operation Thumb wheel Where a comp
3. Glasgow 1986 Defence Standard 00 25 Human Factors for Designers of Equipment Part 8 Auditory Information Ministry of Defence Glasgow 1989 Department of the Environment Transport and The Regions Mobile Phones and Driving Advisory Leaflet 1998 Federation of Communication Services Safe Communication on the Move Important Advise for Drivers Grandjean E Fitting the Task to the Man London Taylor and Francis 1981 Hardee H L Johnston C M Kuiper J W and Thomas I V E Towards a Method for Evaluating Instrument Control Panel Controls Proceedings of the Human Factors Society 34th Annual Meeting pp 613 617 1990 HUSAT Research Institute QED Quick Ergonomic Design Loughborough University Loughborough Leicestershire UK 1992 ISO 13407 Human centred Design Processes for Interactive Systems 1999 ISO 15005 Road Vehicles Ergonomic Aspects of Transport Information and Control Systems Dialogue Management Principles and Compliance Procedures in preparation ISO 15007 Road Vehicles Transport Information and Control systems Man Machine Interface Definition and Metrics related to the Measurement of Driver Visual Behaviour ISO 15007 2 Road Vehicles Transport Information and Control systems Man Machine Interface Equipment and Procedures related to the Measurement of Driver visual Behaviour Test Report ISO 15007 2 Road Vehicles Measurement of driver visual behaviour with respect
4. Thus controls should be usable in all situations and conditions that are likely to occur eg in darkness while wearing gloves It is therefore advisable that they be tested in such contexts Safety critical design decisions should be documented and reflected in user manuals Complex operations that require the use of both hands or long un interruptable sequences of interactions eg more than 5 keystrokes should be disabled whilst the vehicle is in motion SAE 2364 5 1 1 Location Controls should be easy to reach from the normal driving position and should not obstruct access to other driver controls or displays They should not encroach upon or interfere with normal leg hand and arm movements in order to avoid accidental activation 5 1 2 Layout Each control should e Be usable without inadvertently activating another control e Be located in close proximity to their associated display e Be located so that the driver s hand does not block his view of an associated display e Move ina direction that is consistent with the display High priority controls should be easiest to reach and operate The plane of the displays and controls should be perpendicular to the driver s line of sight The centres of controls that need to be operated non visually should be positioned at least 15 cm apart Defence Standard 00 25 Part 10 1992 5 1 3 Design The design of all controls used should be suitable for their function see Table 2
5. 9 the objective of the guidelines in this document is to produce a user friendly synthesis of current knowledge and provide up to date guidance on where to locate more detailed information These guidelines can be viewed as a companion document to the IVIS HMI Safety Checklist that was developed in order to assess safety issues raised by existing or planned IVIS systems Stevens et al 1999 It is likely that if the advice provided in these guidelines is followed any resulting system is more likely to be assessed favourably based on an evaluation by this or an equivalent Checklist In addition to issues raised by the Checklist these guidelines include a discussion of some legal issues raised by IVIS see section 8 The manufacturers responsibility with respect to system design or failure and indeed the status given to guidelines checklists and compliance assessment methods is becoming increasingly important and complex While this document aims to present objective and measurable solutions to many design concerns there is likely to remain some element of subjectivity for example as to what is and is not acceptable in terms of whether IVIS will create problems for drivers rather than help them Ideally systems should be designed taking account of safety issues at all stages However many new systems are likely to pose unique challenges for designers in achieving an optimal human machine interface and IVIS designers may ha
6. IVIS system may be used in the same vehicle They need to be aware of and consider the safety issues relating to physical or electronic interference between systems and ensure that where systems are integrated with a shared display the system that is currently operational is clearly identifiable by the driver Where a visual display is to be shared between different systems conflicts between the systems should not occur In the event of a conflict arising the system should prioritise and present any time critical information first Similarly there should be no conflicting auditory outputs from different systems or conflict between visual and auditory messages 5 DRIVER SYSTEM INTERFACE INPUT CONTROLS VISUAL DISPLAYS AND AUDITORY INFORMATION 5 1 INPUT CONTROLS The primary function of a control is to transmit information Sanders and McCormick 1992 The system controls should be designed so that they are easy for the driver to use without adverse impact on the primary driving task see section 7 2 2 Adverse impact on the driving task occurs when badly designed controls induce negative consequences on the ability to drive safely Stevens et al 1999 In vehicle controls should be designed for the intended user group This requires a clear decision as to who the user group is together with compatible instructions and publicity to support this decision The user group may include disabled users as well as older and weaker drivers
7. Research Group Swedish National Road Administration Vagverket Technical Research Centre of Finland VTT Terrafix Toyota Transport Canada TRW Center for Automotive Technology Visteon Corporation Volvo Webraska Mobile Technologies 55
8. and familiar icons where possible e dialogue should not contain information that is irrelevant or rarely needed Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility Eliminate unnecessary information e maintain display inertia make sure the screen changes little from one screen to the next within a functional task situation unless new information is being presented e use concise unambiguous wording for instructions and messages e use a balanced screen layout with plenty of white space around text blocks at least 50 white space for text screens e keep backgrounds simple and muted e group information logically e structure the information rather than just presenting a narrative format Organise information into a small number of chunks e functionality should be clear Hidden functions tend to stay that way e allow users to tailor frequent actions 6 9 SYSTEM DIALOGUE IN A MOVING VEHICLE System dialogue refers to the communication and interaction between the driver and IVIS Only IVIS tasks that do not directly or indirectly increase the risk of collision or injury to vehicle occupants or other road users may be suitable for use while driving Complex information and control actions should not be designed for use in a moving vehicle because they can be too distracting for the drivers Guidelines to be followed include e any IVIS functions th
9. other distinguishing feature on a product presents themselves as its producer The responsible organisation will typically be the vehicle manufacturer or the system supplier The use of IVIS functions intended by the supplier for use while driving that are used by the driver in a manner or way that is not intended and may lead to negative consequences 53 Primary driving task Reflection The activities that a driver has to undertake while driving navigating manoeuvring and handling a vehicle including steering braking and accelerating Reflection is the generation of a secondary image of an object as a result of light from the object bouncing off intermediate surfaces Note that this is relevant for IVIS in a number of ways e Light from a light emitting display travels to another surface or via several surfaces producing a secondary image of the display screen for example on the windscreen This is most likely to be perceived by the driver when there is high contrast between the secondary image and its background such as against the windscreen during darkness e Light from an external source eg the sun streetlights or other bright objects is reflected by the display surface into the driver s eyes see also Glare above Supplier Usability Workload The organisation s responsible for design and production of the system which designate the envelope of use for the system and provide related documenta
10. the testing of a system thus assessment data should be retained in the event of product liability claims or the granting of a licence for it The functionality of many in vehicle information systems is likely to extend to a duty of care on information service providers and may provide wider scope for claims of negligence 8 6 CONSUMER PROTECTION Section 2 of the 1987 Consumer Protection Act introduces strict liability in respect of defective products According to Section 3 of the Consumer Protection Act a product is defective when it does not provide the safety that a person is entitled to expect taking all circumstances into account These circumstances include e its presentation advertising user manual etc e the time when the product was put on the market hence the state of the art defence e the use which can be reasonably expected which includes foreseeable misuse Products must be designed for reasonably foreseeable use not just intended use This requires that the range of actual use is considered and this includes misuse Specific examples of misuse of driver information systems might include e using excessively long glances at the information screen e using a function which is accessible while driving despite the supplier s instruction not to do so e placing so much trust in the system s directions that mandatory road signs are ignored e using digital map information that is out of date In this regard
11. to transport information and control systems ISO 2575 Road Vehicles Symbols for Controls Indicators and Tell Tales 5 Edition 1995 ISO 3461 1 General Principles for the Creation of Graphical Symbols Part 1 Graphical Symbols for Use on Equipment 1 Edition 1988 ISO 3958 Road Vehicles Passenger Cars Driver Hand Control Reach 1977 ISO 4040 Passenger Cars Location of Hand Controls Indicators and Tell Tales 3 Edition 1997 49 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 ISO 4513 Road Vehicles Visibility Method for Establishment of Eyellipses for Driver s Eye Location 1 Edition 1978 ISO 5128 Acoustics Measurement of Noise Inside Motor Vehicles 1 edition 1980 ISO 7000 Graphical Symbols for Use on Equipment Index and Synopsis gva Edition 1989 ISO 7001 Public Information Symbols 2 Edition 1990 ISO TR 3352 Acoustics Assessment of Noise with Respect to its Affect on the Intelligibility of Speech 1 Edition 1974 ISO TR 7239 Development of Principles for Application of Public Information Symbols 1 Edition 1984 ISO TR 9511 Road Vehicles Driver Hand Control Reach In Vehicle Checking Procedures Edition 1991 Nicolle C et al Identification and Grouping of Requirements for Drivers with Special Needs CEC DRIVE 11 Project V2032 TELAID Deliverable No 3 Available from HUSAT Research Centre Loughborough Universi
12. 15 dB or more Sorkin 1987 However to avoid a startle response the signal should not exceed ambient noise by more than 25dB Edworthy 1994 The signal level is a matter of balancing the listener comfort against message audibility 5 3 3 Frequency Auditory information should always lie within the range of human hearing ie 200 8000Hz but it is recommended in practice that it should lie between 500 and 4000Hz ISO 15006 1 It needs to be designed however such that a driver is not prevented from hearing interior or exterior warnings 5 3 4 Auditory information presentation When multiple sounds are used within complex systems the sounds should be designed as an integrated set By doing so the audibility of the signals with one another and background noise can be optimised Robinson 2001 5 3 5 Speech Designers should ensure that when using speech to convey messages e the system should give immediate feedback ie within lt 250 ms to the driver e messages should be short and simple and should not need to be referred to later e if messages cannot be presented in a short sentence the most important information should be presented at the beginning of the message and could be repeated again at the end e the vocabulary used should be familiar to drivers and should avoid using similar sounding words or phrases e messages that require an urgent action should be a single word or a short sentence and should be understood immediate
13. 45 EMC Suppression of radio interference produced by spark ignition engines fitted to motor vehicles EEC 78 316 Interior fittings of motor vehicles identification of controls tell tales and indicators 45 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Endsleigh M R Toward a Theory of Situation awareness in Dynamic Systems Human Factors 37 1 pp 32 64 1995 Endsleigh M R Measurement of Situation Awareness in Dynamic Systems Human Factors 37 1 pp 65 84 1995 European Commission HMI TF European Statement of Principles on human machine interface for in vehicle information and communication systems Expansion of the principles 1998 European Commission 2000 53 EC Commission recommendation of 21 December 1999 on safe and efficient in vehicle information and communication systems A European statement of principles on human machine interface 2000 European Community Directive 74 60 EEC Eysenck M W Principles of Cognitive Psychology Lawrence Erlbaum Associates UK 1994 Galer M D and Simmonds G W R Ergonomic Aspects of Electronic Instrumentation A Guide for Designers SAE SP 576 1984 Gish K W and Staplin L Human Factors Aspects of Using Head up Displays in Automobiles A Review of the Literature DOT HS 808 320 Washington DC NHTSA 1995 Great Britain Road Traffic Driver licensing and information systems Act London HMSO 1
14. 988 Green P Estimating compliance with the 15 second rule for driver interface usability and safety Paper presented at the Human Factors and Ergonomics Society 43 Annual Meeting Houston Texas 1999 HARDIE V2008 Deliverable No 1 Survey of Man Machine Interface Standards and Legislation Requirements for Driver Information 1992 Health and Safety at work Act 1974 Chapter 37 Her Majesty s Stationery Office London 1974 Highway Code Law RTA sections 2 and 3 1999 International Standard JSO 15006 1 Road Vehicles Transport information and Control systems Man Machine Interface Auditory Information Presentation Part 1 Requirements International Standard SO 15008 1 Road Vehicles Ergonomic Aspects of In Vehicle Presentation for Transport Information and Control Systems Part 1 Specifications 46 30 31 32 33 34 35 36 Sie 38 39 40 Al 42 International Standard SO 9241 Part 3 Ergonomic requirements for office work with visual display terminals VDTs Visual display requirements International Standard SO CD 16951 N287 ISO TC 22 SC 13 WG 8 Road vehicles Ergonomic aspects of transport information and control systems Procedure for determining priority of on board messages presented to drivers 2000 International Standard SO DIS 17287 Road vehicles Ergonomic aspects of transport information and control systems procedure for assessing suitabili
15. Distraction Internet Forum United States Department of Transportation National Highway Traffic Safety Administration NHTSA www nrd nhtsa dot gov driver distraction Washington D C 2000 47 43 45 46 47 48 49 50 51 52 53 54 Ranney T A Mazzae E Garrott R and Goodman M NHTSA Driver Distraction Research Past Present and Future Driver Distraction Internet Forum United States Department of Transportation National Highway Traffic Safety Administration NHTSA Washington DC 2000 www nrd nhtsa dot gov driver distraction Robinson G S Lee S E and Casali J G Auditory warnings and displays Issues relating to design and selection In International Encyclopaedia of ergonomics and Human Factors edited by Waldemar Karwowski Volume 1 Taylor and Francis London and New York 2001 Ross T Midtland K Funch M Pauzi A Engert A Duncan B Vaughan G Vernet M Peters H Burnett G and May A HARDIE Design Guidelines Handbook Human factors guidelines for information presentation by ATT systems DRIVE II Project V2008 Commission of the European Communities 1996 Rothergatter T Carbonell De Waard D and Brookhuis K A On the measurement of driver mental workload Traffic and Transport Psychology Theory and application Elsevier Science Ltd Oxford pp 161 71 ISBN 0 08 042786 3 1997 SAE 2364 Navigation and Route Guidance Function Accessibility Wh
16. LATED ISSUES 7 1 GENERAL There are a number of general safety issues that need to be taken into account in the design of IVIS The main concerns are driver overload and attentional demands that can distract the driver from the primary driving task Systems can be a hazard to safety if they are not designed to be compatible with driving The use of in vehicle systems must not directly or indirectly increase the risk of collision or injury to vehicle occupants or other road users Drivers must be able to use in vehicle systems easily effectively and satisfactorily and in a way that is compatible with and suitable for driving In order to be safe and compatible with driving VIS must have good usability and not be distracting Some IVIS design guidelines for optimising ease of use and avoiding distraction are presented in this section 7 2 DRIVER DISTRACTION 7 2 1 Definitions In order to understand how a driver might be distracted from a task it is first necessary to introduce the concept of attention to a task Attention has been defined as the selectivity of cognitive processing that involves focussing or concentrating on one area of thought in order to deal with it effectively Eysenck 1994 When drivers attempt to attend to more than one stimulus at a time their attention becomes divided and if a secondary task is difficult or demanding they may become distracted from the primary task The literature provides a number of
17. YDTLR TRANSPORT LOCAL GOVERNMENT REGIONS aa DESIGN GUIDELINES FOR SAFETY OF IN VEHICLE INFORMATION SYSTEMS by A Stevens A Quimby A Board T Kersloot and P Burns Transport Research Laboratory PA3721 01 TRL LIMITED a tye PROJECT REPORT PA3721 01 DESIGN GUIDELINES FOR SAFETY OF IN VEHICLE INFORMATION SYSTEMS by A Stevens A Quimby A Board T Kersloot and P Burns Prepared for Project Record UG 340 IVIS Guidelines Client TTT Division DTLR Client Contact Mr G Rai Copyright TRL Limited February 2002 This report prepared for Mr G Rai TTT Division DTLR must not be referred to in any publication without the permission of Mr G Rai The views expressed are those of the author s and not necessarily those of Mr G Rai The authors of this report are employed by TRL Ltd The work reported herein was carried out under a Contract placed on 5 July 2000 by the Department of the Environment Transport and the Regions now the Department of Transport Local Government and the Regions Any views expressed are not necessarily those of the Department These Guidelines contain advice on the design of in vehicle information systems They are for guidance only and do not purport to be full or accurate statement of law TABLE OF CONTENTS Page 5 DRIVER SYSTEM INTERFACE INPUT CONTROLS VISUAL DISPLAYS AND 1 INTRODUCTION 1 1 BACKGROUND A wide variety of in vehicle information systems I VIS current
18. act digital control input device with readout is required 5 1 4 Discernibility Designers should ensure that controls are easily discernible during daylight and darkness They should use different methods to aid recognition such as using colours shapes sizes locations textures and possibly sounds The advantages and disadvantages of the different methods are set out in Table 3 When different size controls are used to aid discernibility these should be limited to a maximum of three distinct sizes within one functional area Table 3 Advantages and disadvantages of different discernibility methods Adams 2001 Type of coding Mode of operation Improves visual identification A v v Improves non visual identification tactile 1 Advantages Location Shape Size Labelling Colour Aids identification under low levels when of illumination and coloured lighting illuminated illuminated May aid in identifying control position settings Requires little Gf any training is not subject to forgetting 2 Disadvantages May require extra space Affects manipulation of the control ease of use Limited number of available coding V categories May be less effective if operator wears gloves Controls must be viewed ie must be within visual areas and with adequate illumination present Controls should be separated by distances that are sufficient to avoid two buttons being pressed inadvertently It should be re
19. at are accessible but not designed for use when the vehicle is in motion must be clearly indicated as being restricted e long sequences of interactions with the system should not be required Drivers should be allowed to interrupt the sequence at any time without consequence e there should be a balance between the breadth and height of menus The number of choices should be limited to three or four options to minimise the complexity and interaction time e an off or mute option should be available 34 e system response eg feedback confirmation to driver input should be timely lt 250ms and clearly perceptible e avoid unnecessary attention grabbing techniques eg Boeing s Dark and Silent cockpit metaphor Do not blink or beep unless absolutely necessary e prioritise information e no low priority system initiated information e drivers should be able to initiate and control the pace of interaction with the system no time critical responses should be required when providing input to the system e keep the user informed about system status e do not display information when the driver is busy although this guideline is for more advanced intelligent systems eg GIDS Michon 1993 If an IVIS task is too distracting it can either be re designed or removed Complex IVIS functions can be locked out to prevent in transit use These functions should be accessible only when the vehicle is stationary 35 7 OTHER SAFETY RE
20. attention has also to be given to the second hand vehicle market to understand how second owners of products use them including for example when digital maps become increasingly out of date 43 8 7 HEALTH AND SAFETY The Health and Safety at Work Act 1974 describes the general duties of an employer for the welfare of his employees Although not directly applicable to designers or manufacturers it is worth noting that the Act is becoming more relevant to the in vehicle environment when it is used as a workplace If this is the case any employer requiring or expecting their staff to use vehicle based information systems should ensure that the safe operation of the vehicle is not compromised and that the driver or other road users are not put at risk Designers should also recognise that the Act may result in a requirement that employers ensure that drivers who are expected to use an IVIS as part of their work are provided with adequate training with the system 8 8 SUMMARY OF IMPLICATIONS FOR MANUFACTURERS The driver is responsible for safe control of the vehicle and this includes appropriate use of in vehicle information systems However the driver is also entitled to protection from defective products that do not provide the level of safety that the driver expects in use Manufacturers may protect themselves to some extent from product liability claims by e designing for reasonably foreseeable misuse e designing in fail safe mode
21. ave serious safety implications in some circumstances In general it is advisable not to present inaccurate information and to ensure that a system will fail safe Systems need to take into account the accuracy of the information provided by external sources for example GPS for vehicle positioning and allow for possible inaccuracies in this information As well as being accurate information also needs to be unambiguous and not open to misinterpretation by the driver 7 6 ROUTING AND SAFETY System design may need to take account of a changing road network The IVIS needs to be able to deal with e temporary diversions eg caused by road works or accidents e minor changes to network eg new one way systems e upgraded roads eg from single to dual carriageway 38 If drivers are required to leave the suggested route the system needs to recognise this and recalculate the route guidance provided If maps are used they will need to be updated on a regular basis Designers should build in provision for updates and notify the user of how this will be done 39 8 THE LEGAL SITUATION FOR UNITED KINGDOM These guidelines deal with the current legal situation with regard to IVIS that apply in the United Kingdom although similar provisions do apply throughout Europe When examining the legal situation concerning any new in vehicle device it is necessary to consider each of the following Responsibilities Traffic la
22. cation system This philosophy is re enforced by the Highway Code Paragraph 128 which states There is a danger of driver distraction being caused by in vehicle systems such as route guidance and navigation systems congestion warning systems PCs multi media etc Do not operate adjust or view such a system if it will distract your attention while you are driving you MUST exercise proper control of your vehicle at all times If necessary find a safe place to stop first The penultimate sentence as indicated by the MUST is a reference to the 1988 Road Traffic Act Sections 8 2 and 8 3 According to the Road Traffic Act a failure on the part of a person to observe any provision of the Highway Code shall not of itself render that person liable to criminal proceedings but such a failure may in any proceedings whether civil or criminal tend to establish liability Thus the Highway Code does not have the power of law but it quotes from other laws and has the status of a Code of Practice such that a court is likely to expect drivers to follow its provisions 8 3 LICENCES AND CONTRACTS The operation of in vehicle devices may be subject to the granting of licences Road Traffic Driver Licensing and Information System Act 1989 concerns licences specifically for systems requiring instillation of equipment on public highways and or systems providing turn by turn route guidance in accordance of prevailing traffic and road network conditi
23. cognised that drivers may have different manual dexterity on occasions may not be able to devote total concentration and may sometimes be wearing gloves In order to avoid confusion between positions there should be more than 2 5 cm between button centres but also see section 5 1 2 For size coding to be effective controls must be sufficiently different in size to make them different from each other see Table 4 Table 4 Minimum dimensions for finger operated controls MIL STD 1472F 1999 Type Operation Dimension Contact surface Clearance centre to centre g force area Gloved hand Bare hand Push button 1to8N 8mm 80 mm 25 mm 15mm 5 1 5 Control input stereotypes Controls should be designed in conjunction with conventional stereotypes For example turning a control clockwise is normally associated with up right or increase while counter clockwise is associated with down left or decrease Under highly stressful or high workload situations people often refer back to learnt 20 stereotypes and if what they perceive does not meet their expectations they are more likely to make mistakes 5 1 6 Colour Colour should be used effectively to aid the layout of controls The meaning of the colour coding should be clear and should conform to stereotypical norms for example red for alarm and amber for warning Red green and blue yellow combinations should be avoided since th
24. coming information and transforms this into an information output Distracting and potentially disabling effect of bright light in an otherwise relatively dark scene that interferes with visual attention and selection Note that for the in vehicle context this can occur in a number of ways a External light usually sunlight falls on the visual display reducing display contrast and makes the information on the screen more difficult to see from the driver s normal viewing position b The display is itself too bright and causes distraction from the road scene and other in vehicle displays and controls This is most likely to be apparent to the driver in low ambient light conditions Graphics IVIS input controls Luminance Machine Pacing Manufacturer Misuse Symbolic drawing or illustration used to present visual information without the use of text or numbers All elements of the systems interface through which the driver provides control inputs These include turn knobs push buttons touch screens joysticks pedals and microphones The light emitted from a display SI units of cd m This occurs when the speed at which the user must interact with the system is determined by the system rather than by the user The person or organisation responsible for system construction The term includes the designer component suppliers and system integrator plus system suppliers who by putting a name trade mark or
25. definitions for distraction Janssen 2000 used distraction to refer to the capture of the driver s attention by information that is irrelevant to the driving situation to a degree where insufficient attention is left for the primary task Ranney et al 2000 defined driver distraction as any activity that takes a driver s attention away from the task of driving Some authors use driver distraction to mean the allocation of attention to the system displays or controls that has a negative effect on driving performance 7 2 2 Driving The primary task is to monitor and control the vehicle s lateral and longitudinal position along a safe path At the simplest level this involves controlling steering and speed tasks that with time and experience become almost automatic requiring little cognitive effort At more complex levels additional manoeuvres will be required for example overtaking and manoeuvring appropriately at junctions and roundabouts These tasks demand greater cognitive effort and the introduction of additional information for example from a route guidance system while undertaking these tasks will create an unwanted distraction Allen et al 1971 Tijerina et al 2000 A distraction can be visual auditory cognitive or biomechanical Ranney et al 2000 Something that takes driver s visual attention away from the road or changes their 36 glance behaviour is a visual distraction eg reading a map Listening to music while dri
26. do not fit into the definition of IVIS employed here e be easily usable from the driver s preferred seating position e be fixed securely such that it is free from vibration e provide information on system compliance with any standards and regulations Designers also need to be aware that e if the front seat passengers as well as the driver are likely to use the system their use should not interfere with the driver in any way e IVIS need to be designed and installed in order to be crashworthy and to minimise injury potential in the event of an accident 4 2 PHYSICAL AND VISUAL ACCESS TO DRIVER CONTROLS AND DISPLAYS Compliance with recommended control and display locations should ensure that the driver s ability to maintain full and safe control of the vehicle is not affected by installation of the IVIS BSI DD235 1996 The system should be installed such that e it does not obstruct or interfere with existing controls or displays required for the primary driving task from the driver s normal seating position e it does not obscure the driver s view of the road scene through the windscreen side windows or rear view EEC 71 127 EEC 77 649 e if the physical position of the system can be altered adjusted so that it does obscure the driver s view the manufacturer s instructions should clearly state the intended position for use while driving 4 3 COMPATIBILITY WITH OTHER SYSTEMS Designers need to recognise that more than one
27. e objectives of a system considered in Stage 1 are normally formulated in very general terms eg navigate the driver to destination The performance specifications describe what the system needs to do to meet its objectives eg transmitting both visual and auditory information These should reflect the context in which the system will be used and the skills available among the users The IVIS also needs to be compatible with the primary driving task ISO DIS 17287 2000 Stage 2 defines what functions need to be performed to meet the objectives and performance specifications formulated in Stage 1 eg select destination select route provide directions etc In Stage 3 the basic design is defined After this more attention can be given to the human machine interface in Stage 4 In Stage 5 attention is given to the documentation and training that is needed for the end user Testing and assessment Stage 6 is typically considered after this stage but ideally should be carried out throughout the whole design process Identify the intended users of the 1 Determine objectives system eo P erformanc Identify and define user needs which specifications f the system will address seri What functions need to be performed 2 Definition of the yp m rather than how functions need to be system functions y performed Allocation of function 3 Basic design p e Specifications of huma
28. eferences to supporting text The present document can be seen as providing an updated version of the BSI Code of Practice that takes account of recent developments in the area 1 3 HOW TO USE THE GUIDELINES The guidelines are intended to be a first reference document that can be used at each stage of the design process In some cases critical issues will arise at the initial conception stage depending on the system being considered Ideally assessment should be a continuous part of the entire design and development process The guidelines provide both normative data and an extensive list of further useful reference documents If there are queries about the ergonomic information provided in these guidelines initial reference should be made to the named authors at TRL Ltd If the query relates to the current status of the guidelines with respect to its legal status within UK and or EU queries should be addressed to Transport Technology and Telematics Division of the UK s Department of Transport Local Government and the Regions DTLR TRL Ltd and DTLR accept no responsibility for the currency or comprehensiveness of the materials contained within these guidelines Although great care has been taken in the compilation and preparation of these guidelines to ensure accuracy TRL Ltd cannot in any circumstances accept responsibility for any errors or omissions 1 4 FORMAT OF DOCUMENT This document provides a systematic review of the many factor
29. ehind the guidelines will thus be largely transferable Similarly they are not intended to deal with advanced driver assistance systems ADAS that aim to assist drivers with vehicle control such as speed setting following at a safe distance and lane keeping The guidelines are primarily aimed at systems designed for private car drivers rather than those used in fleet management systems which can for example monitor driver activity and provide drivers with work related instructions or performance feedback The guidelines will of course be largely transferable and applicable to systems used by individuals in the course of their work for example by drivers of fleet cars HGVs PSVs and ambulances These drivers may equally be required to enter system passwords and receive task information by means of visual displays However additional issues concerning for example employer and employee responsibilities are covered only very briefly within this document see section 8 7 There are various sources of information relevant to the design of IVIS see section 9 For example the BSI Code of Practice BSI DD235 1996 sets out to provide recommendations to assist designers manufacturers suppliers and installers regarding safety related issues affecting systems used by drivers in transit It overviews key human factors design considerations eg control and display location training system interaction etc It provides both normative data and r
30. ersections The system should be designed in such a way that the allocation of driver attention to the system displays or controls remains compatible with the attention demands of the driving situation 7 3 SYSTEM FAULT AND INPUT ERROR WARNINGS If the IVIS is inoperative at the start of a drive when activated by the driver or fails during it the driver needs to be made aware of the situation Drivers will make mistakes while using IVIS so the systems must be tolerant of user input errors It must be possible to easily recover from errors and the consequence of potential errors must be minimised Error messages should be expressed in plain language no codes precisely indicate the problem and constructively suggest a solution Some other guidelines for system faults and warnings are European Commission 1998 and ISO 15005 currently being approved the driver should have immediate and clear feedback for input errors use reminders or warnings only as appropriate provide user centred wording in messages avoid ambiguous messages use plain language and indicate the precise problem avoid using threatening or alarming messages unless appropriate e use specific constructive words in error messages eg avoid general messages such as invalid entry and use specifics such as please enter your name e make the system take the blame for errors eg systems should respond unrecognised command rather than illegal com
31. ese colour combinations might be confusing for people who are colour blind The use of too many colours should also be avoided a maximum of five different easy to distinguish colours is recommended BS 5378 Part 1 1980 Colours should be used consistently throughout the system Colours should have the same meaning on all the screens that the system can use It should be noted that when using colour visual displays colour after effects can occur such as the McCullogh effect which causes pink snow if green text has previously been read Floating of display elements can also occur with high colour saturation thus colour must be used with care and with due consideration to changes caused by variations in luminance and contrast 5 1 7 Lighting The lighting of the controls should be adequate to identify the required control but should not distract the driver Drivers should be able to adjust the level of lighting 5 1 8 Feedback Control operational feedback should be adequate appropriate and timely Operational feedback is adequate if it is obvious to the driver that a change has occurred in the system and that this change is a consequence of the input A timely response should usually be given within 250ms European Commission 1998 The user should be able to hear or see immediately if they have made an input error or incompatible choice The system should provide error messages in plain language and indicate the precise prob
32. f the system eg use maps listen to radio e What are the likely conflicts between system use and normal safe operation of the vehicle e What functionality must be provided by the system to avoid misuse by the driver 2 1 3 System users Information about which drivers the system is intended to help needs to be taken into account in the design process and the system should ideally be designed with all users in mind whether male female young old able bodied or disabled While some systems are intended for all drivers some will target particular groups The type of user may be characterised by driver demographics such as their sex and age or by the reason for the trip For example holiday drivers might want to receive different information to high mileage business drivers It is important to appreciate that drivers differ markedly in their physical perceptual and cognitive abilities and systems need to be designed with this in mind Where appropriate these guidelines give special considerations to other user groups that have distinct needs eg the elderly In addition attitudes and emotional state will vary between drivers and these may critically influence their behaviour Drivers do not perform consistently while driving they experience lapses of concentration suffer from fatigue and stress whether social work or journey related and sometimes consume alcohol In contrast drivers or developers undertaking an on road assessme
33. formative style 5 3 AUDITORY INFORMATION 5 3 1 General Designers should only consider the use of auditory information when this is the most appropriate modality for the type of information being delivered Auditory information is most suitable when the driver s attention needs to be gained when the message is short and simple and does not need to be referred to later Where possible and appropriate the combination of visual and auditory information presentation should be used Ideally the system should enable the last auditory message to be repeated by means of a simple button press or voice command as the driver may have been distracted 28 during the initial presentation of the auditory information or may have forgotten or not have understood the message It should be possible to control whether the auditory information is turned on or off and feedback about the current status of the auditory information should be presented every time the system is turned on 5 3 2 Volume It should be possible to hear the auditory output under all driving conditions at a level that will not startle the user The volume of auditory output should be adjustable over a reasonable range in most circumstances between 50dB A and 90dB A is suitable Higher than 90dB A should be avoided Sounds containing different frequencies should all be presented at an appropriate volume usually this can be achieved if the signal exceeds the ambient noise by
34. he IVIS instructions the driver should be clear about how the system will respond Ideally the system should recognise the failure to respond and compensate for the non compliance by offering a confirmation message and updated advice 6 2 VISUAL INFORMATION PRESENTATION Designers should ensure that when the in vehicle system consists of different functions eg route guidance entertainment and e mail these should be fully integrated Preferably the system should have one interface and features such as colours formats and menus should be consistent throughout the different functions This is a particularly important consideration if drivers have access to information from 3 party providers eg through the Web portal A display should be organised in such a way that drivers can direct their attention to the relevant information and find it easy to understand and respond to that information The display should therefore be simple in overall density local density and grouping e overall density the percentage of the total number of characters or symbols that could occur in the display space High information density may cause overload and increase errors and difficulties in finding appropriate information e local density the amount of space that is filled around a symbol item Blank space provides structure in a display 31 e grouping considers how close items are and how likely it is that they are perceived as groups On first
35. he ratio should be lower for more prominent dynamic and safety critical information The more critical the information the wider the character should be up to a ratio of 1 6 25 The width of a character see W in Figure J is very dependent on the height of that character The relation between the width and the height of the character should be between 0 5 1 and 1 1 whilst a ratio between 0 6 1 and 0 8 1 is recommended A wider symbol should be provided for more prominent dynamic and safety critical information The more critical the information the wider the character should be up to a ratio of 1 1 Character spacing refers to the horizontal space between adjacent characters This is usually expressed in terms of the stroke width of the characters The space between the characters should be a minimum of one stroke width Wider spacing should be used for more prominent dynamic and safety critical information The more critical the information the wider the spacing should be although legibility will be reduced if it becomes excessively large 25 5 2 3 6 Font The type of font used to display text is an important factor in legibility and comprehension e The font type should be clear and simple Sans serif fonts are recommended eg Arial Helvetica not Times e No more than two different fonts and two types of emphasis eg bold or underlining should be used HARDIE 1996 5 2 3 7 Case e The use of mixed or sentence ca
36. hine interaction driver behaviour responsibility and safety Systems must comply with the rules that allow vehicles and drivers to be part of public road traffic and the rules of traffic law Also the civil and penal liability of the driver keeper of a vehicle and the rules on the product liability of manufacturers and suppliers are relevant Drivers should ensure that they have access to manufacturers instructions and take adequate steps to be aware of their content before driving on the road They should not use a system until they are able to do so safely and may need to allow themselves a period of training or familiarisation 8 2 TRAFFIC LAW The construction and use of vehicles on public roads is governed mainly by Part II of the Road Traffic Act 1988 Under this the Construction and Use regulations set out 40 in detail a number of requirements on aspects of vehicles such as steering vision instruments and equipment eg speedometers and audible warnings The Road Traffic Act also describes driver responsibility and offences related to dangerous careless and inconsiderate driving Drivers are expected to be responsible for the proper control of their vehicle That is not to say that they are solely and always responsible for everything as some aspects of the vehicle s performance are outside of their control eg Advanced Braking Systems Drivers are therefore expected to be in control of the operation of an information communi
37. ile Driving Recommended Practice Sanders M and McCormick E J Human Factors in Engineering Design 5 Edition McGraw Hill Inc New York 1993 Sorkin R D Design of auditory and tactile displays In Handbook of Human Factors New York Wiley pp 549 76 1987 Stevens A Board A Allen P and Quimby A A safety checklist for the assessment of in vehicle information systems a user manual PA3536 00 Transport Research Laboratory Crowthorne U K 1999 Tijerina L Kiger S Rockwell T H and Wierwille W W Final Report Supplement Task 5 Heavy vehicle driver workload assessment protocol Report No DOT HS 808 417 Washington D C National Highway Traffic Safety Administration 1995 Tijerina L Parmer E and Goodman M J Driver workload assessment of route guidance system destination entry while driving A test track study Proceedings of the 5 World Congress on Intelligent Transport Systems 12 16 October 1998 Seoul Korea CD ROM 1998 Tijerina L Johnston S Parmer E and Winterbottom M D Driver Distraction with Route Guidance Systems NHTSA DOT HS 809 069 2000 Wierwille W A Visual Sampling of In Car Displays In A G Gale et al Eds Vision in Vehicles IV pp 271 280 Elsevier Science Publishers 1993 48 10 BIBLIOGRAPHY 10 11 12 13 14 15 16 17 Defence Standard 00 25 Human Factors for Designers of Equipment Part 7 Visual Displays Ministry of Defence
38. ing considered The first method is essentially a test of how well the system meets a set of design guidelines which may be performance criteria set by the producer It may be based on such requirements as the anthropometric and ergonomic standards for physical sizing locations of controls and the labelling and display of information see section 5 and is usually conducted by human factors experts against some pre specified objective criteria There are different systematic approaches to these expert evaluations such as the TRL DETR IVIS Checklist Stevens et al 1999 and the Heuristic Evaluations method Nielsen 1993 both of which have been found to be effective for evaluating IVIS Both of these methods can identify key usability and safety issues They give problems a severity rating to guide re engineering priorities and provide solutions rather than just a critique Both of these expert methods can be used very early in the development phase and can be task based or holistic A second method evaluates the system more quantitatively with respect to driver and system performance Although there is no single indicator for acceptable usability or safety performance this method will need to take account of issues such as reliability validity and sensitivity ISO DIS 17287 2000 Reliability can be indicated for example by two types of system error errors of omission where a stimulus is not detected when the hit rate for stimulus de
39. ing direct responses Although drivers should not be able to do this whilst driving and available options should be within reason The setting of personal preferences should however be restricted within safe limits in order to prevent the inadvertent loss of information When maps are displayed within the vehicle the system should distinguish clearly between system modes For example it should be clear when the vehicle is in the middle of the display re centred map mode or when the vehicle moves relative to the stationary map normal display mode 6 5 MENU FACILITIES It should be easy to navigate through the system menus It should be simple to return to the start or escape from a dead end These options should be consistent throughout the system There should be an appropriately small number of menus submenus and final options The number of choices per menu should be limited to three or four Frequently used functions should have dedicated single function control keys rather than be located within the system menu structure 32 For interactions involving more than one screen the driver should not have to remember information from one screen to the next 6 6 TEMPORAL INFORMATION The system s response to driver input should be timely see section 5 1 8 and clearly perceptible If a response takes longer than 250ms the system should inform the driver that it has recognised the input and is busy preparing a response European C
40. isplay tie together to form a contour of a picture text or symbol With an increasing number of pixels the contour of the picture will appear clearer HARDIE 1996 5 2 3 5 Character and spacing Characters used in a display should be large enough to read in the moving vehicle H L Figure 2 Character height width and stroke lt _wWw gt S 24 The minimum required character height see H in should be a visual angle of 15 This angle describes the relationship between the viewing distance and character height as shown in Figure 3 The following equation should be used to determine the required character height H tana x D H character height in mm amp angle created at the eye by the character height and distance from the display ee Figure 3 D distance from the driver s eye to the display in mm The minimum requirement of 15 is recommended for static or non critical information Mourant 1976 Since a vehicle is in motion and vibrates reducing legibility it is recommended that character height is at least 24 ISO 15008 integrated 2000 With a visual angle of 20 at a normal reading distance in a vehicle 700mm the minimum character height would be 4 mm e Angle a height eye lt I lt distance from driver to display Figure 3 Minutes of arc The ratio between the stroke width see S in Figure J and character height should be between 1 12 5 and 1 6 25 T
41. iver s gaze out of the front windscreen onto the road ahead Visual displays showing high priority information during driving should be located within 15 of the driver s vertical viewing position and ideally 15 horizontally HARDIE 1996 with a maximum separation of 30 Priority should be based on the display s relevance to driving criticality urgency and frequency of use This may require trading off various functions at the design stage ISO CD 16951 N287 2000 Displays showing high priority information and multifunction integrated visual display screens should be located high on the dash board and not low in the centre stack console Only very simple information that is rarely used by the driver should be located in the centre stack console 5 2 3 Legibility 5 2 3 1 General To ensure legibility of information the designer needs to consider not only the position of the visual display but properties such as brightness contrast size and resolution These should be such that the displayed information is clearly legible during daylight and darkness and does not cause visual discomfort or distract the driver when not being directly viewed 5 2 3 2 Brightness The brightness luminance of the overall display should appear uniform to drivers While in some conditions the overall uniformity of display luminance may vary it is best to avoid this within a particular element of the display eg a sentence The brightness of the dis
42. leigh 1995a 1995b Reaction time to events eg peripheral detection task Olsson and Burns 2000 Vehicle Lane position variance Tijerina et al 1995 Tijerina et al 1998 Unplanned lane departures Steering reversals Steering and speed unpredictable patterns Mean speed speed variance Minimum headway and headway variance Minimum time to collision Number of critical incidents crashes speed on impact entropy ie and 3 SYSTEM DOCUMENTATION AND USER INSTRUCTIONS 3 1 GENERAL Designers should consider the advantages of providing systems where the need for complicated instructions or training is minimal The design process should recognise the need to provide instructions written or otherwise for how the system can be used and importantly how it should be used without compromising safety These should be assessed eg for comprehension and cover all relevant aspects of installation operation and maintenance Designers need to ensure that they play an active role in the production of any manuals and documentation produced for end users Any instructions provided should be durable European Statement of Principles 1998 and contain the advice that they should be retained within the vehicle so that future owners will be able to learn about the safe operation of the system Instructions should also inform drivers not to use the system until they are content that they have ideally received sufficie
43. lem It is even more important for the system to inform the driver accurately about any malfunction of the system Examples include when an address is entered that does not exist the error message should say address does not exist rather than error input When the sensor calibration data is lost the system should inform the driver that accuracy of the route guidance system is reduced There can be safety implications when there is a difference between the actual function of a system and the driver s expectations based on previous information and experience Therefore it is important for the system to make it clear to drivers when there is a change in status or a malfunction which modifies the system s performance so that drivers can modify their behaviour accordingly 21 5 1 9 Touch screen controls Current generations of touch screens are not appropriate for use when mobile since they provide no tactile feedback concerning control orientation location separation from one another or function and consequently cannot be accurately operated eyes off Interaction with touch screens often demand long glance duration and consequently a high degree of visual resource allocation in order to locate and activate the control button this type of interaction is not conducive to safe performance of the driving task If touch screens are used in vehicles they should be simple to use and suitable for the function they serve the controls
44. ll stages of any assessment conducted either utilising appropriate internal resources or engaging the services of external consultants where necessary Potential IVIS end users should also be involved The amount of training and or experience that these drivers have with the system will depend on what exactly is being tested If it is the comprehension of the system instructions provided that are being assessed then the users should be inexperienced However if the trials demand driving in busy traffic then a certain amount of familiarity with the system would be advisable Both male and female drivers the young and elderly should participate The required number of drivers participating in the evaluation depends on the salience of problems being investigated and their probability of occurrence Lewis 1994 It is unlikely that a system evaluation would be effective using anything less than 10 12 end users Nielsen 1993 2 2 4 Assessment method and criteria There are a number of general methods of IVIS assessment One method considers the ergonomic requirements of the specific VIS design A second method assesses the IVIS in situ but not necessarily on the road according to human and system performance criteria Other methods can involve the use of focus groups mathematical models and user trials The most appropriate method to use will depend on when in the design process it is being applied and what aspect of the system is be
45. ly e the system should be able to cope with background noise and should not be influenced by it a signal to noise ratio SNR of around 5dB A should be sufficient to ensure audibility ISO CD 15006 1996 29 e where messages contain instructions they should be presented in a logical order for example rather than turn left in half a mile the message should be in half a mile turn left 30 6 DRIVER SYSTEM INTERFACE DIALOGUE MANAGEMENT 6 1 GENERAL INFORMATION PRESENTATION In general there are four types of information that can be conveyed to the driver Galer 1983 warnings advisory information diagnostic information entertainment Warnings provide information that is of vital importance to the safe operation of the vehicle and in vehicle systems Advisory information is also useful for the safe operation of the vehicle and in vehicle systems but this tends to be vehicle status information that is less time critical and severe eg telltales Diagnostic information explains the condition of the vehicle for maintenance purposes Some vehicle information can also be provided through the entertainment system eg traffic bulletins via the audio system System design should ensure that information presented to the driver should be correct consistent and compatible with the road network The quantity of information presented to the driver should not be excessive When it is not possible for the driver to comply with t
46. ly exist and many more will become available in the near future These systems aim to help the driver by providing information for example about routes traffic congestion and accidents Because these systems can provide drivers with real time information and are becoming increasingly sophisticated and thus more useful there is a growing concern that they may interfere with the primary driving task and thus compromise safety Similarly the possibility of providing drivers with an in vehicle office environment with telephone fax machine e mail and computer raises serious safety concerns as do some advanced entertainment systems While these systems should come with advice about not using them while driving as is currently the case with mobile phones the driver may be tempted to ignore such advice In addition to the distraction issue there are also potential safety problems with respect to the driver being given incorrect information by the IVIS for example advising them to drive the wrong way down a one way street It is thus essential that drivers be reminded about their responsibilities regardless of information provided by these systems The guidelines in this document are intended to alert designers and manufacturers of IVIS to some legal and ergonomic issues relevant to safety Since there are already a sizeable number of relevant guidelines standards and codes of practice in existence see Technical References in section
47. mand 37 e avoid automatic switching to other modes when desired functions become inaccessible e make user actions easily reversible allow undo commands and other escape routes from operations 7 4 BEHAVIOURAL ADAPTATAION Another safety concern for IVIS is behavioural adaptation as drivers become more familiar and experienced with a particular system they may adapt modify the way in which they interact with it and the information it provides The Organisation for Economic Co operation and Development OECD 1990 refers to behavioural adaptation as those behaviours which may occur following the introduction of changes to the road vehicle user system and which were not intended by the initiators of the change Designers should consider that potential safety benefits and behavioural impact of new in vehicle systems may be reduced by behavioural adaptation for example drivers may consider using route guidance systems to help them find their way in fog when without the IVIS they would not travel In this context the more advanced and sophisticated the system and the more useful information it offers the driver the more such adaptation and reliance will become a factor The only effective way of assessing or evaluating such concerns are by instigating long term trials 7 5 ACCURACY OF INFORMATION Designers need to recognise that presenting drivers with inaccurate or untimely information is likely to h
48. manufacturer claims are of the appropriate standard are considered acceptable For after market installation in the UK it has generally been assumed that equipment such as information screens can be regarded as de minimus additions to a vehicle that would not impact on existing approvals Thus after market information and communication systems are not required to comply with Directives such as interior fittings requirements that specify minimum radii avoiding sharp edges and impact friendly design However it appears sensible from the liability perspective for after market manufacturers to be 42 knowledgeable about the requirements for new vehicles and follow the same requirements 8 5 TORT LIABILITY Although the liability of parties to an agreement is governed by the contracts between them they may also be liable in tort particularly to third parties such as drivers with whom they have no contract Tort liability requires it to be established that the defendant for example a manufacturer or software provider specifically did something to cause harm or more likely did not do something to prevent harm negligence In order to establish liability in negligence the claimant must first show the existence of a duty of care and then that a breach of that duty took place There could for example be negligence in the design manufacture of an in vehicle system or in the fitting of it within the vehicle There could be negligence in
49. n performance requirements Task analysis description e Characteristics of human machine interfaces e Work space Serene ant 4 Interface design nd e Displays 4 Testing an assessment Controls Dialogues Etceteras e Materials that promote acceptable human performance 5 Facilitator design id e Instruction manuals Performance aids Training devices and programs Figure 1 Stages in design process adapted from Sanders and McCormick 1992 Information about the system user characteristics and how the system will be used should be established early in the design process and used to facilitate both the design and assessment process These principles are equally important where new functionality is being added to existing functionality to ensure that HMI issues are considered for the overall integration of new and old Human factors professionals should be involved throughout the design process 2 1 2 System requirements Detailed design issues that need to be considered vary with the type of system or systems being developed and their functionality At a very early stage of the design process a number of questions should be asked For instance e What do drivers need systems to do e What functionality must be provided by the system to meet these needs e By what means did drivers address their needs prior to availability o
50. ns on the part of the potential users it should promote road safety and compliance with existing traffic regulations and recommendations for road and vehicle use System instructions should be provided in the users native language or a form designed to be understood by the driver The instructions should e be correct simple and clear relevant well defined and presented in a logical order e clearly state which aspects of the system are intended for use by the driver when driving and those aspects that are not intended for use by the driver when driving e identify the intended user groups if specific skills or capabilities are required or if the product is unsuitable for use by particular users e include actions required in the event of a system failure and a trouble shooting or help section to easily locate specific information e state clearly that the driver retains absolute responsibility for the safe operation of the vehicle and compliance with current traffic regulations regardless of any information provided by the VIS e provide a statement of compliance with other systems Manufacturers should make the assumption that if they do not either directly stipulate that a particular function should NOT be used while driving or physically disable a function when the vehicle is moving then drivers are likely to assume it can be used on the move In order to ensure the continued safe operation of the IVIS and to ensure the dri
51. nt instruction to do so safely or have at least had the opportunity to familiarise themselves sufficiently with the system 3 2 COMPLIANCE WITH REGULATIONS STANDARDS AND RECOMMENDATIONS Standards and guidelines have been developed to assist designers and manufacturers in producing usable products that meet the minimum safety requirements Documentation should therefore be developed and retained to provide evidence of compliance with regulations standards and recommendations and the consideration of human machine interface HMI issues Regulations frequently relate to safe system use and crashworthiness in the event of an accident Thus designers need to consider the safety of vehicle occupants and how they can be protected from injury caused by the IVIS in the event of an accident 3 3 PACKAGING INFORMATION AND INSTRUCTIONS Designers and manufacturers of IVIS whether factory fitted or off the shelf must not misrepresent what a system can do or how it should be used in a way that might encourage unsafe use This applies to both what the consumer is told at the point of sale and any publicity or other sales materials that are displayed or produced EC Code on Advertising 1995 Designers and suppliers should therefore ensure that the packaging accurately conveys system functionality and makes the user aware of system capabilities and limitations It should not encourage unsafe or illegal use nor create unrealistic expectatio
52. nt of a new system may be highly motivated and focussed and consequently unrepresentative of the wider user group It should also be recognised that driver behaviour during initial use eg during testing and assessment may be very different from that adopted after the driver has habitually used the system for a number of months 2 1 4 Road and traffic conditions The designer should recognise that the system will not always be used in the conditions for which it was originally designed and that conditions can vary markedly Assessment should therefore involve a wide range of road and traffic conditions 2 1 5 Environmental conditions Designers need to consider the range of environmental conditions in which their systems are likely to be used These should include darkness bright sunlight heavy rain or fog etc Driving at night changes the driving task and IVIS design issues considerably Different lighting conditions also demand specific design features for example an anti glare screen to compensate for bright sunlight 2 2 SYSTEM ASSESSMENT 2 2 1 Importance of assessment Designers should recognise that system assessment is important at all stages of design both for improved product development and to reduce potential liability problems in the future A formal assessment methodology or procedure should ideally be applied to ensure a continuous and consistent assessment schedule It is advisable that user assessments ideally with ine
53. of similar function Controls should behave consistently Avoid changing modes where user interaction requires different actions than in other states eg adaptive multifunction buttons Organise data fields to match user expectations Inconsistent systems ie those that do not match driver expectations will be more difficult to use and take more time to learn Inconsistent systems will cause more errors The severity of this problem will depend on the system function 6 8 SIMPLICITY AND QUANTITY Simplicity refers to the ease with which IVIS tasks are performed and information understood IVIS systems should not allow or demand any complex tasks The amount of information on display should therefore be restricted Complex IVIS tasks 33 will distract the drivers attention from the primary task This will reduce driving performance and compromise road safety Visually displayed information should be such that the driver can assimilate it with a few glances that are brief enough not to adversely affect driving If the information cannot be acquired in a few brief glances driver workload and visual distraction may increase Driving is adversely affected when the driver is distracted or overloaded which may result in situations where their actions or lack of actions increase the risk of a crash In order to maintain simplicity the following principles should be adopted European Commission 1998 BSI 1996 e use single words or simple
54. ommission 1998 Visual information should be presented for a sufficient length of time that allows the driver to observe it in their own time when other task demands are low or remains displayed re presentable until the driver acknowledges that he has observed it or the message becomes out of date The IVIS should be free from machine pacing The driver should be able to control the pace of the interaction with the system It should be possible to interrupt a sequence of interactions and resume again at the point of interruption or at another logical point When new information arrives that is directly relevant to the current driving situation eg a coming turn a suitable indication should be given in advance of a driver decision Two or three messages should be used sequentially including the time and or distance to the event 6 7 CONSISTENCY Information presented to drivers should be consistent and compatible with the road network Consistency is also how well a system matches a driver s expectations VIS handling appearance and behaviour should conform to the driver s expectations The driver s expectations can be a function of their experience with the system or similar systems and commonly accepted conventions Expectations will also vary with individual differences such as knowledge culture and gender Message terminology and icons should be consistent between displays Colours should be consistent between displays
55. ons Other licences that may be relevant depending on the exact nature of the system include Radio Telecommunications licence Infrastructure Planning consents Service licences eg for digital information transmission Copyright licences for software or mapping Manufacturers should for example comply with the Statement of Principles on human machine interface HMI for in vehicle information and communication systems European Commission 2000 53 EC A contract is an agreement between parties enforceable by law that sets out obligations duties and liabilities However under English law a person cannot restrict his liability for death or personal injury caused by his negligence or intent 41 The exact nature of contracts between component manufacturers system manufacturers software providers and vehicle integrators will have a bearing on how liability is apportioned for the development and use of all in vehicle information systems 8 4 TYPE APPROVAL The Type Approval process serves the purpose of ensuring that agreed and acceptable levels of performance in general and safety in particular are provided in new road vehicles This process gives the consumer some level of protection and enables free trade between countries via international harmonisation of legal requirements Standards should not be confused with Type Approval Standards are voluntary agreements that can become law if they are quoted in an EC Directive o
56. onsistent throughout the VIS system and should not be too detailed or complex as this can increase the time taken to identify appropriate information 26 e Where possible the graphics features should be functionally grouped but not cluttered e When unfamiliar symbols are used a text label of limited text should accompany them but should otherwise be avoided e For ISO 2575 symbol and tell tales or similar a matrix 32 pixels x 32 pixels is the minimum ISO 9241 3 e Commonly accepted or standardised symbolic icons should be used Campbell et al 1998 ISO 4040 e The comprehension of non standard and unfamiliar symbols should be tested 5 2 6 Screen image stability The screen display should not vibrate or flicker to an extent where information becomes blurred the eye is capable of detecting luminance flicker of up to 90Hz in some circumstances Vibration or flicker are likely to increase reading time and consequently the time required to complete the task and thus will increase visual distraction from the driving task HARDIE 1996 5 2 7 Image blinking Blinking or flashing of any visual image should only be used to attract attention and inform about critical conditions For attracting attention a single blink frequency of 2 to 3Hz with a duty cycle of 50 is recommended If legibility of the displayed information is required a single blink rate of 1 3 Hz to 1Hz with a duty cycle of 70 is recommended ISO DIS 15008
57. ow to assess the balance between an IVIS that can provide regular possibly small benefits over a long period of time but may very infrequently result in a single extreme negative outcome For example failing to warn a driver about severe congestion on the route ahead or instructing the driver to make an illegal manoeuvre at a junction This question is likely to depend critically on the consequences and or frequency of the system failure although accurately identifying such infrequent events during assessment trials conducted over a limited period of time may prove very difficult Any significant degradation in performance when driving with the VIS should be a concern and if any basic safety related tasks are compromised the decision should be taken to restrict their use to when the vehicle is stationary Table 1 Measures of IVIS Safety and Usability Performance System Performance Driver and Vehicle Performance Efficiency Number of button presses Number of errors Task success rate Task completion time eg the 15 second rule Green 1999 Driver workload Subjective rating attitudes eg usability and usefulness ratings Psychophysiological measures eg heart rate and heart rate variability Secondary task performance Driver Eye movement behaviour eg mean and maximum glance duration glance frequency eyes off road time Wierwille 1993 Situation awareness Ends
58. play should be adaptable to changes in ambient light eg day or night to ensure that the display is legible in all ambient light conditions 23 5 2 3 3 Contrast The contrast ratio see formula below describes the relation between the luminance of the foreground and background This should be a minimum of 3 1 whilst a ratio of 5 1 is recommended HARDIE 1996 Too high contrast can cause problems of glare while too low contrast slows down the reading process The ratio of area average luminance of the display and of the surrounding luminance balance should not exceed 10 1 ISO 15008 integrated 2000 Contrast L foreground Loackground Loackground Lforeground Luminance of the foreground Loackground Luminance of the background Reflections and glare visible to the driver on both displays and windscreens reduce legibility and should be avoided for example through provision of a display brightness control appropriate display surface texture and finish appropriate colour choice appropriate image polarity use of a recess or cowl Designers should ensure that any reflection and glare reduction or contrast enhancement techniques of this type do not cause the display to contravene other relevant standards 5 2 3 4 Resolution The resolution of the display should be high enough to show the driver solid images of information via symbol or text The number of pixels measures a display s resolution The single pixels of a d
59. r 366 pp 102 115 British Standards Institution Code of Practice DD235 Guide to In Vehicle Information Systems 1996 British Standards Institution Safety Signs and Colours Parts 1 Colour and Design British Standard 5378 Part 1 London British Standards Institution 1980 Campbell J L Carney C and Kantowitz B H Human Factors Design Guidelines for Advanced Traveller Information Systems ATIS and Commercial Vehicle Operations CVO Washington DC Federal Highway Administration FHWA RD 98 057 1998 Consumer Protection Act 1987 Chapter 43 Her Majesty s Stationery Office London 1987 Defence Standard 00 25 Human Factors for Designers of Equipment Part 10 Controls Ministry of Defence Glasgow 1992 Department of Transport Driver Information Systems Code of Practice and Design Guidelines Revision D Final Draft 1994 DIN EN 60073 Basic and safety principles for man machine interface marking and identification Coding principles for indication devices and actuators IEC 60073 1996 German version EN 60073 1996 Published 09 1997 EC Code Advertising in context of road safety Final report WP3 Directorate General for Transport of the European Commission 1995 Edworthy J The design and implementation of non verbal warnings Applied Ergonomics 25 4 pp 202 210 1994 EEC 71 127 On the Approximation of the Laws of the Member States Relating to the rear view Mirrors of motor Cars 1971 EEC 72 2
60. r Type Approval specification Standards may also be held up as representing the state of the art although as they are often the outcome of negotiations they may not actually reflect this Designing a product to meet government or industry standards does not guarantee that it will not be found defective Traditionally courts have taken the position that all standards provide at best lower limits for product acceptability Codes of practice Statements of principle etc are likely to be viewed in a similar way if derived through negotiation Across Europe two systems of Type Approval are currently in place One is based around EC Directives and provides for the approval of whole vehicles vehicle systems and separate components The other is based around ECE United Nations Regulations and provides for approval of vehicle systems and separate components but not whole vehicles The importance of Type Approval will depend on the IVIS being designed for example introducing in vehicle display screens may impact on the following Directives Field of view 77 649 EEC EMC 95 54 EC Interior fittings 74 60 EEC Controls amp Indicators 78 3 16 EEC EMC 95 54 EEC Automotive regulations between the EC and ECE have close parallels and there is mutual recognition between many of them Whole vehicle type approvals are valid for the life of the vehicle Replacement parts in theory should be identical but in the UK parts that the
61. rs SNR Signal to Noise Ratio GLOSSARY Ambient Light Surrounding light environment Ambient Noise Brightness Contrast ratio Convention Dialogue Driver controls Driver displays Feedback Foreseeable Misuse Surrounding noise environment The perceived light from a display SI units of cd m It is the sum of all light falling on a display and coming from display Describes the relation between the luminance of the foreground and luminance of the background Established customary practice Related set of successive inputs and outputs involving the IVIS and the driver These include accelerator brake clutch if fitted steering wheel gear changer parking brake horn light switches turn indicators washers and wipers hazard lights de mist controls These include speedometer all warning lights mandatory control labels and mandatory tell tales Response from the IVIS giving information to the user about an input action taken further action that is required or a change in system state Use of the IVIS in a way that is not intended but which the suppliers might be expected to have anticipated 52 Free standing Equipment Function Glare Equipment that is not securely mounted or installed within the vehicle It may require hand held operation for example a remote control device or a mobile phone Operation or activity carried out by the IVIS that is executed on reception of in
62. s e marketing the product accurately e controlling maintenance and repair operations e designing safe systems This means that producers of VIS may be required to carry out extensive testing to check system reliability and check on driver responses to possible system failure or error Importantly it will be necessary to provide the end user with pertinent advice about how the system should and should not be used Another aspect of product liability is the development risk defence provided in some national laws in accordance with the EEC Directive This defence is based on the argument that applying the state of science and art at the time of marketing of the product meant that any defect could not be detected Any producer would be advised to both seek professional guidance and comply as fully as possible with any existing Code of Practice provided to assist with development and testing This is likely to help demonstrate in a court of law that he has exercised his duty of care although such compliance will not be a guarantee that the duty has been discharged 44 9 10 11 12 13 14 REFERENCES Adams S K Input Devices and Controls Manual Controls Iowa State University Ames IA 50011 USA In International Encyclopaedia of Ergonomics and Human Factors Ed Karwowski W Taylor and Francis 2001 Allen T M Lunenfield H and Alexander G J Driver Information Needs Highway Research Record Numbe
63. s that need to be considered in the design process of IVIS systems Section 2 describes the different stages of the design process and considers briefly what each stage entails and the possible need for conducting assessments at the different stages Section 3 deals with the documentation and user instructions that may need to be provided with the system Section 4 provides guidelines if required about how the IVIS should be fitted within the vehicle Section 5 covers ergonomic issues of how the driver interacts with the system with respect to controls visual displays and the use of auditory information Section 6 discusses more complex interface or dialogue issues Section 7 considers more general safety related aspects of IVIS such as the need to provide the driver with accurate and timely information Section 8 considers the legal situation and issues of liability and responsibility Sections 9 and 10 provide References and a Bibliography respectively The Bibliography includes references that are interesting further reading but are not specifically referred to within these guidelines A list of Abbreviations and a Glossary of Terms are given in section 11 2 SYSTEM DESIGN AND ASSESSMENT 2 1 SYSTEM DESIGN 2 1 1 General Figure 1 shows one representation of the main stages in the system design process Before a system can be designed there must be a reason for it to exist th
64. se with a standard combination of lower and upper case letters makes characters and messages more easily recognisable and should be used for written text rather than using all capitals or lower case e However if resolution is low eg less than 32 x 32 pixels and descenders eg p g y etc are not possible the use of upper case only may be considered as a second best alternative 5 2 4 Colours Colours should be e coded such that their meaning is clear and should conform to stereotypical norms DIN EN 60073 1997 e used to make it easier to find the required information under both day and night time viewing conditions e chosen so that red green and blue yellow combinations are avoided Colour should not however be used for actual messages as this would increase the reading time The use of too many colours should also be avoided A maximum of five different easy to distinguish colours is recommended excluding black and white It may be appropriate to have three levels of priority indicated by colour eg 1 Red Alarm 2 Amber Warning and 3 White Information status 5 2 5 Symbols and graphics The use of graphics and symbols should be appropriate to their function and should conform to stereotypical norms The advantages with symbols compared with text are that they erase language barriers and can be recognised faster and from a greater distance The graphics features or symbols should be c
65. sight of a visual display areas of high contrast attract the attention Contrast between different parts of the display should therefore be created where appropriate to aid the direction of attention and understanding of the information being presented McDougall 2001 6 3 CHOICE OF DISPLAY MODALITY Designers should avoid presenting complex visual information to the driver of a moving vehicle if possible A visual display should only be used if this is more compatible with the function than other modalities such as speech The driver should be able to assimilate visual information with a few glances which are brief enough not to adversely affect driving A brief glance refers to glance duration of around 1 second representing the normal case and a maximum single glance of 1 5 seconds Wierwille 1993 If the system provides non safety related dynamic visual information for example navigation parking or traffic information it should be possible to be switched into a mode where that information is not provided to the driver of a moving vehicle Non driving related information eg TV or video should be disabled or presented in such a way that the driver cannot see it while the vehicle is in motion DD235 1996 6 4 INDIVIDUAL PREFERENCES Designers should recognise the advantages of systems that allow drivers to tailor the presentation of information to their own preferences and driving requirements especially for information requir
66. tection should be high and errors where a response occurs when no stimulus is present false alarms when the false alarm rate should be low Some examples of reliable and validated measures are provided in Table 1 on page 13 Designers need to recognise that system assessment should never jeopardise the safety of the participants subjects the evaluator or the general public With this aim desktop laboratory or driving simulator assessments may be used to conduct preliminary assessments and to identify more serious safety and usability concerns before conducting trials in real road situations In some cases it may be judged worth conducting initial trials on a test track Ideally final safety assessment should be performed during road tests It is also necessary to tailor any assessment with respect to the existing situation or base case For example if the VIS provides route guidance it is necessary to consider whether its use should be compared with traditional route finding techniques with information provided by road signs and with or without the use of a conventional map that might be held or placed on the passenger seat In this case test drives could be undertaken for example in an unfamiliar location and compare performance of the IVIS in relation to other in vehicle tasks eg tuning a radio Note should be made of all the difficulties encountered by drivers during these assessments There is also the complex issue of h
67. tion Ease with which the IVIS can be used Physical and or cognitive demands made on an individual at any given moment 54 12 ACKNOWLEDGEMENTS The authors and DTLR customer would like to thank all those individuals and organisation who have contributed to the development of these Guidelines by identifying problems with available documentation and commenting on earlier drafts of this document These organisations with apologies to any left out included Automobile Association Autosonics Ltd Daimler Chrysler Department of Transport Local Government and Regions DTLR European Union DGVII now DG TREN ERTICO Federal Highway Research Institute BASt Germany Fiat Research Centre Global Telematics Heriot Watt University Edinburgh Idesta Ltd Institute for Road Safety Research SWOV Netherlands Jaguar Loughborough University HUSAT Magneti Marelli S p A Monash University Victoria Australia Microbus MIRA Ltd previously Motor Industry Research Association Motorola Netherlands Organisation for Applied Scientific Research TNO National Highway Traffic Safety Administration NHTSA USA National Institute of Research on Transport and Safety INRETS France Nissan Technical Centre Europe Open University Ergonomics Petards Civil Systems Ltd Portable Multi Media Provector Ltd PSA Peugeot Citro n Rover Royal Automobile Club RAC Saab Secured by Design Southampton University Transport
68. to the Specification of Driver Visual Behavior Using Video Based Techniques Stokes A Wickens C and Kite K Display Technology Human Factors Concepts SAE publications 1990 UNECE Regulation 21 E ECE 324 Uniform conditions concerning the approval vehicles with regard to their interior fittings United Nations Economic Commission for Europe Regulation 21 Uniform Provisions Concerning the Approval of Vehicles with Regard to their Interior Fittings 1998 Van Cott H P and Kinkade R G Human Engineering Guide to Equipment Design 1972 EC Code on Advertising in the Context of Road Safety VII 671 1995 EN 1995 Virizi R A Usability testing how many subjects are enough 1994 Warnes A Rough B and Sixsmith J Factors in elderly people s driving abilities Deliverable 6 Project V1006 DRIVAGE of the European DRIVE programme From A Warnes Department of Geography Kings College London WC2R 2LS 1991 Zwahlen H Admas C and DeBauld D Safety aspects of CRT touch panel controls in automobiles Vision in Vehicles II Elsevier 1988 51 11 ABBREVIATIONS AND GLOSSARY OF TERMS ABBREVIATIONS ADAS Advanced Driver Assistance System BSi British Standards Institution DIS Draft International Standard HMI Human Machine Interface ISO International Organisation for Standardisation IVIS In Vehicle Information System OECD Organisation for Economic Co operation and Development SAE Society of Automotive Enginee
69. ty Loughborough UK 1992 PROMETHEUS Thematic Working Group 4 Man Machine Interaction WG4 MMI PROMETHEUS MMI Checklist Version 2 1 PROMETHEUS Office C O Daimler Benz AG Postfach 80 02 30 D 7000 Stuttgart 80 Germany 1991 Rockwell T H Eye Movement Analysis of Visual Information Acquisition in Driving an Overview Proceedings of the 6 th Conference of the Australian Road Research Board 6 pp 316 331 1972 SAE J 1138 Design Criteria Driver Hand Controls Location for Passenger Cars Multi Purpose Passenger Vehicles and Trucks 10 000 GVW and Under Recommended Practice 1977 SAE J 1139 Direction of Motion Stereotypes for Automotive Hand Controls Recommended Practice 1994 SAE J 1050 Describing and Measuring the Driver s Field of View Recommended Practice 1994 SAE J 1052 Motor Vehicle Driver and Passenger Head Position 1997 SAE J 2094 Vehicle and Control Modifications for Drivers with Physical Disabilities Terminology 1992 SAE J 2119 Manual Controls for Mature Drivers 1993 50 34 35 36 37 38 39 40 41 42 43 44 45 46 SAE J 2217 Photometry Guidelines for Instrument Panel Displays that Accommodate Older Drivers 1991 SAE J 287 Driver Hand Control Reach Recommended Practice 1988 SAE J 833 Human Physical Dimensions Recommended Practice 1989 SAE J 941 Motor Vehicle Driver s Eye Locations 1997 SAE J 2396 Definition and Experimental Measures Related
70. ty for use while driving 2000 Janssen W Driver distraction in the European statement of principles on in vehicle HMI a comment Driver Distraction Internet Forum 2000 ittp www nrd nhtsa dot gov driver distraction PDF 789 PDF Khalid H M and Helander M G Automatic speech recognition In International Encyclopaedia of ergonomics and Human Factors edited by Waldemar Karwowski Volume 1 Taylor and Francis London and New York 2001 Lewis J Sample sizes for usability studies additional considerations Human Factors 36 pp 368 78 1994 McDougall S J P and Osborne D J Design and Use of Displays Department of Psychology University of Wales Swansea UK In International Encyclopaedia of Ergonomics and Human Factors Karwowski W Taylor and Francis 2001 Michon J A Ed Generic Intelligent Driver Support A comprehensive report on GIDS Taylor and Francis Ltd 1993 MIL STD 1472F Human Engineering American Department of Defence Design Criteria Standard 1999 http www dodssp daps mil Mourant R R and Langolf G D Luminance specifications for automobile instrument panels Human Factors 18 1 pp 71 84 1976 Nielsen J Usability engineering San Francisco CA Morgan Kaufman 1993 OECD Behavioural adaptations to changes in the road transport system Paris OECD Road Research Group 1990 Olsson S and Burns P C Measuring driver visual distraction with a peripheral detection task Driver
71. ual information presentation is the most appropriate modality to use when information is complex does not require immediate action may need to be referred to again and or is presented continuously Sanders and McCormick 1993 When possible and appropriate the use of both visual and auditory information presentation should be used Visual information presented on the IVIS should appear legible accurate and be presented at the appropriate time The size of the display images should be appropriate to their function High priority visual information requiring immediate 22 action should be more prominently displayed and should be accompanied by an alerting auditory tone Campbell et al 1998 5 2 2 Location For a driver to be in full control of the vehicle and aware of the dynamic road scene there is a broad consensus that apart from brief glances at mirrors or instrumentation the driver s gaze should be directed towards the road scene Visual displays positioned close to the driver s normal line of sight reduce the total eyes off the road time relative to those that are positioned further away Such positioning also maximises the possibility for a driver to use peripheral vision to monitor the road scene for major developments while principally looking at the display The higher priority the information has the closer it should be located to the normal line of sight The driver s normal line of sight refers to the direction of the dr
72. unless extremely simple such as on off should not work by proximity but require light positive pressure for activation and provide auditory control activation feedback Screens activated by proximity detection make it easy to inadvertently activate the wrong control unless the responsive areas are very large 5 1 10 Voice operated controls Designers should note that speech recognition systems may not yet be sufficiently advanced to implement reliably in vehicles Khalid and Helander 2001 Those currently in use tend to have limited vocabularies and are not robust enough to provide high recognition accuracy leading to frequent misinterpretations Additionally vehicle and passenger noise often interfere with the voice recognition system while changes in people s voices due to fatigue and stress can make valid commands unrecognisable Sanders and McCormack 1993 When using speech recognition systems e the vocabulary used should be familiar to drivers and should avoid using similar sounding words or phrases e the system should give immediate feedback ie within lt 250 ms to the driver in regards to the recognition results e the systems recognition accuracy should be high particularly in safety critical situations eg recognition 98 for hit rates and less than 5 false alarm rates e the system must be able to cope with expected amounts of background noise 5 2 VISUAL DISPLAYS 5 2 1 General Designers should note that vis
73. ve problems in discovering what up to date guidance is available and where it can be found These guidelines aim to assist with these issues 1 2 SCOPE AND OBJECTIVES These design guidelines are based on current understanding of ergonomic good practice and cover the many issues that need to be considered when designing and evaluating in vehicle information systems They put safety and usability as a paramount design concern The objective of these guidelines is to provide designers and manufacturers and others within the supply chain with a summary review of the factors that need to be considered in the design process of IVIS in an easy to use format They are not intended as an encyclopaedic collection of all that has been written or is known on the subject The policy adopted was to provide sufficient information such that in most cases further references would not be required However where necessary appropriate references are provided to supplement the information and advice The guidelines primarily deal with systems that provide the driver with information specific to his journey such as congestion incident eg accident warnings or route guidance information Although they are not intended for designers of in vehicle entertainment systems such as radios cassette and CD players or mobile telephones whether hands free or otherwise many of the issues raised eg driver distraction will be similar and the principles b
74. vers eyes e information should only be displayed temporarily in the HUD The HUD should not be used to display information continuously e HUD displays should not be used to present complex information for example detailed navigation information that cannot be processed quickly rather a simple display with very few elements should be used e use images that conform to the road environment eg virtual road signs projected by the roadside 5 2 10 Message Messages presented while driving should not consist of more than four units of information Concrete words which have clear meanings should be used whenever possible McDougall 2001 Numerical data should use accepted and understood units and provide an appropriate level of precision Abbreviations should only be used when it is necessary and should not be used for safety critical information Where abbreviations are used these should be widely known have clear meaning be used consistently and conform to national conventions Where available internationally and nationally agreed standards related to abbreviations should be used European Commission HMI TF 1998 Safety critical information should be given in a command style However the command style should be used infrequently High priority messages such as immediate hazards or vehicle status warnings should be preceded by an auditory alerting tone Messages that convey non critical information should be given in an in
75. vers are aware of their responsibilities the user manual should outline the maintenance requirements of the IVIS including the frequency at which software should be updated 3 4 TRAINING Designers should consider the advantages to be gained by integrating operating instructions within the system or even providing a programmed tutorial as part of the system although this will not always be appropriate or possible The possibility of providing a hands on element to any training should also be considered either in the form of simulated use or an accompanied trial drive again this may not always be a realistic option 4 SYSTEM INSTALLATION 4 1 DESIGNER MANUFACTURER S INSTRUCTIONS Manufacturers and designers of IVIS intended for fitting into vehicles need to provide clear instructions for the location and installation of the IVIS These instructions should be tested for comprehension on a group of end users They should also take adequate steps to ensure that those doing the installation are aware that any IVIS should e be located and fitted in accordance with the relevant regulations standards and manufacturers instructions for installing equipment in vehicles UK Code of Practice 2 1 1 EC Directive 74 60 EEC e not be freestanding within the vehicle Note that the EC European Statement of Principles Expansion HMI TF 1998 does permit some devices eg automatic garage door openers to be free standing but such devices
76. ving could be an auditory distraction An activity that demands thought can be a cognitive distraction if it takes the driver s mind off the road traffic environment eg engaging in a call on a hands free mobile phone Something that requires the driver to lean forward take their hands off the wheel or stretch to operate can be a biomechanical distraction eg adjusting the volume on an entertainment system These biomechanical distractions can force drivers off their normal sight lines and impair their control of the vehicle Many distracting activities that drivers engage in can involve more than one of these four components For example tuning the radio or dialling a mobile phone may involve all four components of distraction Distracted drivers are more dangerous because they may be unable to adequately monitor and control the vehicle s safe path while performing an IVIS task It is the coincidence of driver inattention and the occurrence of unanticipated events eg curve in the road pedestrians crossing that causes distraction related crashes Ranney et al 2000 The driver may try to regulate the consequences of distraction by reducing the attentional demands of the driving task in terms of lowering the amount of effort required to perform it and its level of difficulty for example by slowing down However there will be times when this type of regulatory behaviour is not possible for example when making judgements about time gaps at int
77. w Licences and contracts Type approval Tort liability Consumer protection liability Health and Safety at Work Act 8 1 RESPONSIBILITIES Each person or organisation in the VIS supply chain has responsibilities to ensure that systems do not compromise either the safety of the users themselves or of other road users Importantly they may be required to prove that they properly fulfilled their legal responsibilities in a court of law in the event of some improper functioning confusing information or breakdown resulting in an injury or accident taking place This applies not only to those supplying the system or possibly installing it but also employers expecting their staff to use the system and vehicle hire companies renting or leasing vehicles who should also accept responsibility for maintaining or repairing any system fitted in their vehicle or at least warning drivers that a fitted system is not functioning properly While it can be argued that drivers themselves bear the ultimate responsibility for their own and other road users safety it can also be debated whether they were given sufficient verbal guidance or advice or written instructions about safety aspects of the IVIS Ideally a copy of the manufacturer s user instructions should be provided and remain in every vehicle The provision and use of in vehicle information systems needs to comply with a variety of complex legal issues that deal with human mac
78. xperienced users are conducted at an early stage in order to highlight unexpected circumstances of system use and misuse Even if an IVIS is created with careful adherence to design guidelines and with consideration of user needs it is advisable to conduct final usability trials using both naive drivers as well as experts who might have experience of similar systems Approaches to conducting assessments of safety and usability of IVIS are described in sections 2 2 2 2 2 4 If a new design is based on an existing system and is intended for use in the same circumstances and by a similar group of drivers then a limited assessment by independent experts may be sufficient 2 2 2 When to assess If the system uses elements that have not been tested in vehicles before it is advisable to assess the system s safety and usability early in the design process and again when a prototype system is available In all cases it is advisable to plan and undertake assessment trials throughout the design process Tests should be conducted as soon as the first prototype systems are available Final tests must also be done to ensure the systems are safe for use while driving In some circumstances it may be possible to test pre prototypes using mathematical or structural models mock ups and simulated driving techniques 2 2 3 Who should be involved Designers should involve suitably qualified and experienced ergonomic human factor personnel at a

Download Pdf Manuals

Related Search

Related Contents

CONGRES QEPARTEMENTAL  AVIC-F130 AVIC-F250    Samsung RF195 User's Manual  User manual M2  Table of Contents  

Copyright © All rights reserved. Failed to retrieve file