Effects of emergency lanes and exits and entries in tunnels on driving behaviour : driving simulator studies. On behalf of the Ministry of Transport, Public Works and Water Management, Transport Research Centre AVV.

This report is a result of the European SAFESTAR project RO-96-SC.203 (Safety Standards for Road Design and Redesign). The report covers two driving simulator studies. The first study investigates the effect of an emergency lane inside a tunnel. Experiment 2 investigates driving behaviour on entries and exits inside tunnels. Results from experiment 1 show a rather constant effect of omitting an emergency lane inside a tunnel. Although the effect of decreased lateral space is also available on open roads, the influences on driving behaviour seem to be more clear in case of tunnels. This experiment shows that lateral width influences driving behaviour, but that the presence of a tunnel tube also affects driving behaviour, in the sense that it increases the effects of decreased lateral width. Omitting an entire emergency lane is therefore not to be recommended. If an emergency lane is present, the effects on speed and lateral position are limited. Experiment 2 shows that no unsafe driving situations occurred using an acceleration lane of 350 m, an exit lane of 250 m and `kissing junctions' of 600 m. No clear effects were found of sight distance, and no clear difference was found between open roads and tunnels. This indicated that even though the circumstances in tunnels might be a bit different than on open roads, no special standards seem to be required. However, this experiment only looked at sight distances that are 100 m or more.