Speed behaviour in work zone crossovers. A driving simulator study

Reductions in speed and, more critically, in speed variability between vehicles are considered an impor-tant factor to reduce crash risk in work zones. This study was designed to evaluate in a virtual environmentthe drivers’ behaviour in response to nine different configurations of a motorway crossover work zone.Specifically, the speed behaviour through a typical crossover layout, designed in accordance with the Ital-ian Ministerial Decree 10 July 2002, was compared with that of eight alternative configurations whichdiffer in some characteristics such as the sequence of speed limits, the median opening width and thelane width. The influence of variable message signs, of channelizing devices and of perceptual treatmentsbased on Human Factor principles were also tested. Forty-two participants drove in driving simulatorscenarios while data on their speeds and decelerations were collected. The results indicated that drivers’speeds are always higher than the temporary posted speed limits for all configurations and that speedsdecreases significantly only within the by-passes. However the implementation of higher speed limits,together with a wider median opening and taller channelization devices led to a greater homogeneityof the speeds adopted by the drivers. The presence of perceptual measures generally induced both thegreatest homogenization of speeds and the largest reductions in mean speed values.