Assisting the older driver - SWOV

Assisting the older driver
effects, two routes were used. Both routes contained the same intersections,
but in a different order. The routes can be described as having the same 8‐
shape (see Figure 6.1), with Route 1 starting with the lower round followed
by the upper round (total of 16 km), and Route 2 starting with the upper
round followed by the lower round (total of 18 km). The lower round had
relatively many intersections at which view of the intersection was blocked
by buildings, whereas the upper round had relatively many intersections of
wide roads with dual carriageways. The routes were randomly assigned to
participants after having ranked and matched participants according to their
scores on the SSQ (scored after the test drive during their first visit) and the
Determination test © (see Section 6.2.5). The ranking was done to make sure
that any effects found on functional age would not be caused by group
assignment and to make sure that withdrawal from the study as a result of
simulator sickness would affect all groups equally.
Figure 6.1. Sketch of the road network and the route participants had to drive.
6.2.5. Design and data‐analysis
The experiment was set up using a 3x2xn mixed between‐within design.
Functional age was the classificatory variable (young, middle‐aged and old),
and driver support (yes or no) and intersection design (various types of
intersections; see Section 6.2.4) were the experimental variables (see Table 6.2).
Within‐subjects comparisons were made to test whether the dependent
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