Effects of Advisory ISA and Incentive Program for Not Speeding (IPNS) on Driving Speeds on Community Streets: a Discussion Based on a Field Trial

Abstract

Controlling or reducing vehicles’ speeds on community streets have been an important issue in promoting traffic calming. Recently, on the other hand, the concern over intelligent speed adaptation (ISA) has been growing mainly in European countries. Also, the discussions about rewards or penalties for everyday driving speed compliance to reinforce incentives for speed reduction have started. In this study, we analyzed the effects of Advisory ISA and Incentive Program for Not Speeding (IPNS) on driving speed on community streets, based on data from a 5-month field experiment. According to the results, we found that Advisory ISA had a certain effect on speed compliance in Zone 30 areas, that IPNS applied in the field experiment had high speed compliance effects for community streets which also include narrow streets without posted speed limit, and that the speed compliance ratios in Zone 30 areas kept higher even after the release from Advisory ISA and IPNS.