Dynamic speed limits; effects on homogeneity of driving speed

Homogeneity of driving speed is considered to be an important variable determining traffic safety. A more homogeneous driving speed increases road safety. This study investigates if the introduction of dynamic speed limit systems will contribute to an increase in homogeneity of driving speed and to what extent this can be explained by an increase in credibility of speed limits. In the present study a total of 46 subjects drove twice 12 road sections in a driving simulator. The speed limit system as well as the situational condition had been varied. Homogeneity of the driving speed and the rated credibility of the speed limit in force were assessed. The results show that homogeneity is higher with dynamic speed limit systems than with the regular static speed limit system. More sophisticated dynamic speed limit systems lead to higher homogeneity than less sophisticated systems. The present study shows that dynamic speed limit systems are more credible than the static speed limit system.