Effects on driver behaviour of different signalling schemes of work zones

The paper reports on the outcomes of a study performed with the interactive fixed-base driving simulator of the Inter-University Research Center for Road Safety (CRISS) and aimed at analysing the driver behaviour close to crossover work zones. Four different schemes of signalling were studied. The first one (configuration zero) was consistent with the Italian technical rules for temporary signalling. Further three alternative traffic signs systems were designed based also on the schemes of signalling used in France and in Germany. The four configurations of the crossover work zone were designed on that same section of highway about 6 km long and implemented in the driving simulator. Thirty-five participants drove the driving simulator on the highway with the four different configurations of signalling. The local speed were collected and analysed. For all configurations studied the driver reached the advance warning area at a higher speed than that indicated on the traffic sign. Only at about 400 m from the merging taper the driver reduced the speed but the values were higher than the speed limit. Bringing forward the work zone traffic signs did not produce any effect. The modification in driving behaviour seemed to be suggested, rather than by signs, by the visual perception of the cause of the modification itself. The mean speed was kept below the limits only when there was a physical constraint (the opening median) due to the change roadway. The speed on the shifting taper did not depend upon which lane approaching the work zone was closed but only by the opening median width. Closing the left lane instead of the right lane determined higher deceleration rates on the shifting taper. Such a result could be affected by the lack of confidence with the requested manoeuvre experienced by participants in the experiments.