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Cognitive ergonomics Presentation
- 1. Design Analysis & Enhancement of Citroen C4 Dashboard and Displays Lynne Doran Hazel Kidney Orla Shanahan
- 2. • “ The trend today is to produce automobiles that have exciting systems which enhance the users' driving experiences, however, the distraction potential of these systems has not fully been considered. “ (Tretten, Garling, & Pettersson, 2008)
- 4. Introduction to System • Define boundaries – just the dashboard + displays • Existing use scenarios/task
- 5. Problems Identified • Colours and dials used • Location of information –spread across 4 screens • Warning Lights
- 6. Conceptualization of Problem – Colours and Dials • Target signal similar to noise due to lack of colour or contrast -increase in false alarms and misses • Lower contrast in both colour and size result in driver taking longer glances (Kim, Dey, Lee & Forlizzi, 2011). • Displays are cluttered – self-terminating search(Wickens, 1999) • Rockwell (1988) – when complex displays require glance durations beyond 2 seconds most drivers will experience visual workload problems.
- 7. Conceptualization of Problem – Colours and Dials • Darker characters on light background – in contradiction to UMTRI design guidelines (Green, Levison, Paelke & Serafi, 1994). • Tachometer –should increase in an upward motion not horizontally. • Speedometer is digital – no congruence with mental model of speed (Wickens, 1999) • No colour used in temperature or speed gauges
- 8. Conceptualization of Problem – Location of Information
- 9. Visual Search • Four different screens • Dispersal of information and incorporation of unnecessary information • The operator has to scan each screen, hindering efficiency and increasing the time taken in visual search • Serial Search • Target among stimuli model
- 10. Hazard lights • Target Among Stimuli Model • Operator searched through various distracters for hazard button • Parallel search; target defined using simple rule; as experienced driver knew the hazard icon • Blocked field of vision due to design of vehicle • Once attention was directed, signal was located
- 11. Signal Detection • Target among stimuli • E.g. Kilometers traveled in a single trip
- 12. Warning Lights Warning Signs Seatbelt control
- 13. Conceptualization of problems • Drivers must have their attention on the outside of the car rather than on in-vehicle displays (Baber & Wankling, 1992). • Signal detection • Poor location – More important warning lights further from drivers view • Symbols not obvious or clear
- 14. Poor Location Positioned on the left Positioned on the right Further from drivers viewpoint
- 15. How problems affect drivers • All of these problems contribute to driver distraction, decreased situation awareness and increased mental load • Drivers experience many distractions on the road, in vehicle distractions should be eliminated
- 16. Research Design • Control and Display Survey – car owner, novice user • Field Experiment: Novice user, completed tasks while driving Dependant Variable – Time taken to complete task Testing attention levels
- 17. • “The dashboard does its primary job if it tells you with no more than a glance that you should act. It serves you superbly if it directly opens the door to any additional information that you need to take that action.” Stephen Few
- 20. Proposed Solution • Change colours – increase contrast and introduce pictorial realism • Reduce clutter – simplify display • Move hazard lights • 3 screens –split HDD and HUD dashboard and CS • Move information to more appropriate areas • Move warning lights
- 21. Solution for Colours and Dials • Use of light characters on dark background (Green et al., 1994) • Increase signal strength by using contrasting colours and sizes • Pictorial realism – colour depicting danger on speedometer and temperature gauges
- 22. Solution for Colours and Dials • Adheres to Nielson’s Heuristic Design Principles (1994) • Clutter reduced – unnecessary elements eliminated • Most commonly used instruments in a salient position • System should now be self-evident
- 23. Solution for Colours and Dials • Speedometer – keep digital numbers but include dial around outside – ecological compatibility • Analogue tachometer
- 24. Solution for Location of info • All important information displayed in HUD – speed, fuel gauge, engine temp • Info in HDD – revs, warning lights • Radio, sat nav, heating, in CS – extras will be in CS so changes will not distract driver • Reduces visual search • Improves signal detection
- 25. Solution for Screens • Improve visual search by reducing area necessary for search – 3 screens, split dash (HUD, HDD & CF; Primary and secondary information) • Change shape of screens improve UFOV
- 26. Solution for Warning Lights Study by Tretten, Normark, & Gärling, (2008). • Warnings for serious failures and mechanical operation preferred on the HUD. • Warnings for maintenance/service along with reminders preferred on the HDD. • Response times and driving was perceived to be better when using the HUD. Signal Detection • Important warnings moved to HUD. • Can be detected by a sound.
- 27. Warning Lights Solution • Urgent serious warnings = red • Important warnings = orange. • Icons with text labels are found to enhance performance, compared to icons alone. • Enhance perceptions of usefulness, compared to text alone Wiedenbeck (1999)
- 28. Any Questions?
- 29. References • Baber, C. and Wankling, J. (1992). An experimental comparison of text and symbols for in-car reconfigurable displays. Applied Ergonomics, 23(4), 255-262. • Few, S. (2006). Information dashboard design: the effective visual communication of data. Publisher: O’Reilly. • Nielsen, J. (1994). Ten usability heuristics. Retrieved from http://www.useit.com/papers/heuristic/he uristic_list.html • Regan, M. A., Lee, J. D. & Young, K. L. (eds.) (2008) Driver distraction: Theory, effects and mitigation. Florida, USA: CRC Press. • Tretten, P., Normark, C.J., & Gärling, A. (2008). Warnings and Placement Positions in Automobiles. Luleå University of Technology.
- 30. References • Wiedenbeck, S. (1999). The use of icons and labels in an end user application program: An empirical study of learning and retention. Behaviour & Information Technology, 18(2), 68-82.
Editor's Notes
- The displays in the C4 are cluttered and contain lots of information – in fact the only display which contains relatively little information is the HDD or head down display which as Orla will explain should in fact contain the most important info. Based on the target amongst stimuli model we know that a driver will investigate items one at a time until they find the target, unless the target has some salient feature which the majority of targets in the C4 do not. In the case of the C4 the driver will have to look at a lot of unnecessary information and in more than one location. This will reduce the attention the driver is paying to their primary task of driving and will compromise their performance. In driving a reduced level of performance can have serious consequences with most accidnets being caused by driver distraction. RockwellIn the Citroen c4 there are only 2 colours and very little contrast in size. This means that the driver will have to take their eyes from the road for longer periods of time to find the signal they are looking for – again this brings us back to Rockwell’s 2 second rule. The quicker a driver can find a signal the less distracted they become and the less their driving performance suffers.Drivers may also be less sensitive to signals for 2 reasons – if the signals are constantly occurring or if there is uncertainty about the time the signal will appear (e.g. engine fault light coming on)
- Consider the difference between the radio display and the speedometer; the former is generally digital nowadays, but the latter is typically analog. With the radio, it's important to know exactly what frequency you're on in order to set the right station, but once you do that you generally don't need to look at the display very often. In contrast, you look at the speedometer more often, but the exact value isn't as important. The different requirements lend themselves to different types of displays.In something like speed the exact value is not necessary, knowing the approximate value is sufficient The human eye and brain will notice a needle in a different position quickly and that is what you are looking for, "change" if it is all normal, the needles are in their normal position but if things are changing when they are not supposed to, that needs to get your attention applies to tachometer also
- Driving is still the primary task and should have the highest priority, the previous design of the car did not allow the driver to carry out this primary task efficiently–as it distracted the drivers attention more than was necessary. Our solutions should help the driver improve their driving performance by removing unnecessary distractions and decreasing mental load.
- Green et al., found that light characters on a dark background are more easily distinguishable to the human eye, this will help decrease the time needed to locate a target signal.The digital depiction of speed will be considerably larger than many of the other pieces of information available to the driver as this is one of the most often consulted instruments.Colour will be added to the speedometer, tachometer and temperature gauge. Red has a well established symbolic meaning of danger (Wickens ,1999) and will let the driver know at a glance if they are in troubleThese changes should reduce the time taken to locate a target signal,
- By reducing the clutter the design is following Nielsen’s recommendation of simplicity, it will also reduce the distractors around target signalsIf the system is self-evident users will not need any instruction on how to use it
- Ecological compatibility – physically speed is changing increasing or decreasing – should be represented by an analogue display not a digital one however, Kim et al., (2011) did find that people responded well to both the dial and the large numbers depicting the speed so incorporate both The tachometer will now be an analogue dial – not necessary for the driver to know the exact value depicted by the tachometerBoth of these changes should increase congruence between the drivers mental model, the physical environment and the interface, thus reducing the mental resources the driver needs when consulting these instruments.