This report outlines factors that influence the behaviour of drivers when entering roadway tunnels and, therewith, determine the quality of tunnel entrances. The uncertainty that the tunnel entrance induces in the driver is seen as a major determinant of driver behaviour. This uncertainty is determined by a number of properties of the tunnel entrance. A major distinction is made between properties related to the tunnel design and those associated with the behaviour of the traffic stream. Both types of properties are important for the safety and capacity of tunnels because when driver behaviour changes at tunnel entrances this will reduce the homogeneity of the traffic stream. In order to determine which of the listed properties should be taken into account in the design of tunnels, a method is required for assessing the effects of entering tunnels on driver behaviour and uncertainty. This report proposes a method which can determine differences in tunnel entrance quality on the basis of the amount of visual attention toward the tunnel entrance before it is entered. This method incorporates a continuous registration of the driver's eye movements when he or she is required to look at the tunnel entrance as little as possible. The results of studies with this method will allow tunnel designers to improve the quality of tunnel entrances and, therewith, increase the safety of those tunnels and reduce effects on tunnel capacity. (Author/publisher)
Abstract