REDUCING DRIVING SPEED IN LEPPAVIRTA. EFFECTS ON SPEED AND PUBLIC OPINION

In the summer of 1998 the speed limit in Leppavirta was lowered from 50 to 40 km/h, and physical measures were implemented on one of the two main streets in town, Leppavirta Street. Physical measures consisted mainly of traffic islands on zebra crossings. No physical measures were implemented on Savonkatu street. The object of lowering the speed limit was to reduce driving speeds, which were considered too high. The objective was to determine the effects of these measures on speed and public opinion, and to define how the overall effects on speed and the resulting safety could most reliably be estimated. The mean speed of passenger cars was reduced after lowering the speed limit on Leppavirta street by 5.6 km/h (95% confidence interval -6.1...-5.2 km/h), on Savonkatu street by 2.8 km/h (-3.3...-2.3 km/h), and on a nearby residential street with a constant speed limit of 30 km/h by 6.4 km/h (-7.6...- 5.2 km/h). No effects were observed in Nokia, where speed measurements were performed for comparison. The highest 85% speeds (speeds exceeded by 15% of drivers) were reduced the most. On the residential street the highest speeds were reduced by almost 10 km/h. Even after lowering the speed limit, speeds along most parts of the main streets still exceeded 40 km/h and the percentage of speeding drivers was about 60-70%. The percentage of speeding drivers increased by 20-40% units. Travel speeds were reduced overall by 2-13 km/h, the greatest reductions occurring in directions towards the town centre, where speeds had been greater before the experiment. It was estimated that the reduction in speed cut the level of personal injury accidents by 10-20% and the death risk by 40% throughout the town centre. Almost two thirds of the local residents who answered the questionnaire considered lowering of the speed limit a good decision. Yet the same proportion still considered speeding a problem after the measures were taken. Nearly half the respondents felt that their safety in traffic had improved. Comparing women with men, persons aged over 60 with younger ones, vulnerable road users with car drivers, and drivers who drove less with those who drove more, showed that in each case the former had adopted a more positive attitude towards the lower speed limits and the measures to im-plement them. When asked about the potential of various measures to improve traffic safety, police enforcement and driver training were considered most important. They were also considered more acceptable than imposing a 30 km/h speed limit or physical measures such as speed humps or road narrowing.