Assisting the older driver - SWOV

Assisting the older driver
The first category of priority regulation, right of way, is the only category
that includes intersections at which participants had right of way. These
intersections were excluded from the categories of the other intersection
characteristics. As the need to decide on how to deal with other road users
was expected to be an important prerequisite for complexity of the traffic
situation to influence driver behaviour, having right of way was considered
to be the easiest way of passing an intersection, regardless of the other
characteristics of the intersection. Therefore, the category of right of way can
be added to each classification as its first and easiest category.
Between‐subjects analysis of variance showed that functional age
significantly affected reaction time and fraction missed (See Table 6.6 All
intersections; η 2 = 0.265 and η 2 = 0.268 respectively). Post hoc Bonferroni tests
showed that functionally older participants had longer reaction times and
higher fractions missed than both functionally younger (p = 0.004 and p =
0.003 respectively) and functionally middle‐aged participants (p = 0.017 and p
= 0.019 respectively). To test whether reaction times and fractions missed
differed for different types of intersections, the categories of the intersection
characteristics shown in Table 6.5 were regarded as repeated measurements.
Separate mixed between‐within analyses of variance were carried out for
each characteristic of the intersections. The results of all ANOVAs showed a
significant main effect of functional age (see Table 6.6; Partial eta’s squared
ranging from 0.232 to 0.253 for reaction time and from 0.209 to 0.227 for
fraction missed). The intersection characteristics significantly affected
reaction times and fractions missed as well, except for sight distance. This
intersection characteristic did not affect reaction time, but it did affect
fraction missed.
The characteristic that had the largest influence on variation in reaction time,
was intersection layout (η 2 = 0.355). Post hoc Bonferroni tests showed that
left‐side 3‐way intersections – the intersections that were expected to be the
easiest according to this characteristic – indeed led to significantly shorter
reaction times than roundabouts (p = 0.0002), T‐junctions (p = 0.00002) and 4‐
way intersections (p < 0.000001 for intersections with dual carriageways and
p = 0.000001 for regular 4‐way intersections). Only right‐side 3‐way
intersections did not lead to significantly higher reaction times. On their turn,
right‐side 3‐way intersections led to significantly shorter reaction times than
T‐junctions (p = 0.04) and 4‐way intersections with dual carriageways (p =
0.0002), and both roundabouts and T‐junctions led to significantly shorter
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