Assisting the older driver - SWOV

Assisting the older driver
middle‐aged drivers received the maximum number of messages, only 50%
of the functionally old drivers did. The message regarding an unexpected
one‐way road was always sent in the support condition. The participant
received the message as soon as he was within a distance of 55 m of the
respective intersection; just after he had passed an other intersection.
Workload
Data on workload were available for one intersection for both messages
regarding speed and messages regarding a one‐way street. Mixed betweenwithin
analyses of variance showed that the message regarding speed did
not affect workload; neither reaction time nor fraction missed was affected
(see Table 8.13). Age did affect workload. Functionally older participants had
higher reaction times and fractions missed than both functionally young (p =
0.004 and p = 0.011) and functionally middle‐aged participants (p = 0.002 and
p = 0.004). Another mixed between‐within analysis of variance showed that
the message regarding a one‐way street had affected reaction time. Reaction
times were longer if passing the intersection while being supported. The
main effect of driver support was not significant for fraction missed, but the
trend pointed in the same direction (i.e., an increased workload).
PDT reaction time
PDT fraction missed
dfs F p η 2 dfs F p η 2
Speed
Functional age
ADAS
Functional age x ADAS
2, 35
1, 35
2, 35
8.183
0.505
0.737
0.001**
0.482
0.486
0.319
0.014
0.040
2, 35
1, 35
2, 35
7.116
0.064
1.344
0.003**
0.801
0.274
0.289
0.002
0.071
One‐way street
Functional age
ADAS
Functional age x ADAS
2, 34
1, 34
2, 34
1.196
5.369
0.317
0.315
0.027*
0.731
0.066
0.136
0.018
2, 34
1, 34
2, 34
0.104
2.129
0.017
0.901
0.154
0.983
0.006
0.059
0.001
* p < 0.05; ** p < 0.01
Table 8.13. Results of mixed between‐within ANOVAs for messages regarding speed and
one‐way street.
General driving behaviour
Driving behaviours that can be affected by messages regarding speed and
one‐way streets are speed on road stretches and route errors respectively.
The number of route errors at the intersection with a one‐way street was
smaller during drives with the support system installed. Without driver
support four participants – two functionally middle‐aged and two
functionally old participants – entered the one‐way street despite the ‘do not
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