DRIVER SPEED COMPLIANCE WITHIN SCHOOL ZONES AND EFFECTS OF ?40? PAINTED SPEED LIMIT ON DRIVER SPEED BEHAVIOURS
Two speed surveys were conducted on nineteen school zone sections on roads surrounding twelve Primary/High Schools within the Perth metropolitan area. The first survey was done during the period June to August 2001, prior to 40 km/h pavement speed limit markings, and the second was conducted in November 2001, one month after the treatment. Speed data analysis indicated that on both occasions mean speed was 6 km/h less during the 40 km/h speed limit periods than during the 60 km/h period, 49 and 55 km/h, respectively. Similarly, the differences in the 85th percentiles were approximately 4km/h, 60 km/h compared to 64 km/h. Driver compliance to the 40 km/h speed limits was found to be very low when compared to the speed limit of 60 km/h. The percentage of vehicles travelling in excess of 10 km/h above speed limit during the 40 km/h periods was approximately 49% compared to 5% during the 60 km/h period. The best compliance was observed between 8:00 and 9:00 a.m. and the worst one between 7:30 and 8:00 a.m. Comparison of driver speed behaviours in terms of statistical indices such as mean speeds, 85th percentiles and proportions of drivers travelling through the zones showed no statistical differences between the two surveys, before 40 km/h speed limit markings and after implementation of the markings. The study found that the 40 km/h speed limit markings had no significant effect on driver speed behaviours in addition to the effects inflicted on drivers by the standard regulatory signs.
However, the findings of this study should not be generalized to apply to all school zones located on different types of roads, characterized by high volumes, different functionality, higher speeds or traffic composition. It is recommended that the findings of this study should not, in general, be used as an argument against the 40 km/h speed limit markings within the school zones, but as a case for justification in being more selective in considering the sites for the treatment.