Monitoring speed before and during a speed publicity campaign

Driving speeds were monitored during a period of 16 weeks encompassing different stages of an anti-speeding campaign in the Netherlands. This campaign targeted speed limit violations in built-up areas. The observation periods differed in terms of intensity and media used for the campaign. Small road-side radars, mounted in light poles, were used and registered the speeds on 20 locations in built-up areas. Speeds of over 10 million vehicles were measured. Ten locations had a posted speed limit of 50 km/h; the other ten had a posted speed limit of 30 km/h. Posters were placed at half of each group of locations to remind drivers of the speed limit. The average speed on the 50 km/h roads was 46.2 km/h, and 36.1 km/h on the 30 km/h roads. The average proportions of vehicles exceeding the speed limit were 33.3% and 70.1% respectively. For the 30 km/h roads, the data shows differences in speed and speeding behaviour between the six distinguished observation periods, but overall these differences cannot be logically linked to the contents of the phases and, hence, cannot be explained as an effect of the campaign. The only exception was an effect of local speed limit reminders on the 30 km/h roads. This effect, however, was temporary and had disappeared within a week.