Assisting the older driver - SWOV

Assisting the older driver
8. Effects of a driver support system on workload
and driving performance of older drivers 9
This study examined the extent to which driving performance of ten older (70‐88 years old)
and thirty younger participants (30‐50 years old) improved as a result of the support of a
specific driver assistance system. While driving a suburban route in a driving simulator, a
system provided the driver with prior knowledge on the next intersection by informing him
about 1) priority regulation, 2) safe gaps to join or cross, 3) obstructed view of the
intersection, or 4) an unexpected road situation. The system was evaluated in terms of effects
on workload, driving performance, and user acceptance. The effects of the support system
were compared between participants that differed in functional age, which was based on
scores on three tests of cognitive functioning, relating to reaction time, selective attention,
and visual‐motor coordination.
Messages regarding the priority regulation, obstructed view of an intersection, and safe gaps
to join or cross traffic streams led to fewer and/or less decelerations of relevant other
vehicles. These decelerations were considered to be precursors of a collision; fewer and less
decelerations can therefore be regarded as safer driving behaviour. The message regarding
an unexpected one‐way street led to fewer route‐errors. In general, effects of the messages
were the same for functionally young, middle‐aged and old drivers. Workload was not
reduced by the driver support system.
User acceptance was measured by a questionnaire that was administered to the participants
both before and after they had experienced driving with the support system. At first,
functionally old drivers were more positive about the usefulness and satisfying character of
messages regarding safe gaps to join or cross, on obstructed views of the intersection, and on
unexpected road situations. After the actual experience with the support system, opinions
changed and age differences seemed to disappear.
8.1. Introduction
In the coming decades, there will be growing numbers of older drivers –
those aged 75 and above – suffering from functional limitations that reduce
the quality of driving performance. Various studies have indicated that
Advanced Driver Assistance Systems (ADAS) might provide tailored
assistance for older drivers (see e.g., Färber, 2000; Mitchell & Suen, 1997;
Shaheen & Niemeier, 2001). Taking into account functional limitations such
as decreased divided and selective attention, reduced flexibility of neck and
9
An abridged version of this chapter, which focussed on the results regarding user
acceptance was presented at the second HUMANIST conference on driver needs (Davidse,
Quist, Hagenzieker, & Brouwer, 2006). A similar but revised version will be submitted to a
relevant scientific journal. Another abridged version of this chapter, which will focus on the
results regarding effects on workload and driver performance, will be submitted to another
scientific journal.
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