A study is presented in which two indicators for visual workload of the driver are measured in an instrumentad car while driving on a four- and sixlane freeway. For one-minute periods during which the car passed inductive loops in the road surface, a parameter was computed which is assumed to correlate with traffic safety. This is the weighed Time-to-Collision (TTC). The resesarch question in this report is whether visual workload of the driver, which is also assumed to be related to traffic safety, correlates with weighed localized TTC. If so, this would open the possibility of assessing traffic safety from inductive loop data. In an experiment, which involved twenty subjects, half of the subjects performed a visual detection task which was secondary to driving. Performance on this task is a good indicator for visual workload. The other half of the subjects drove the route without performing a secondary task and a measure for frequency of steering movements was taken as indicator for their visual workload. However, the limited set of data was too low for firm conclusions.
Samenvatting