Previous research generally has found driver compliance with school speed limits to be poor, regardless of the type of school zone signing. The lack of compliance has raised questions as to the use of unreasonably low school speed limits to improve school zone safety. A study was conducted to evaluate the effectiveness of various speed control systems used in Nebraska school zones. One objective of this study was to determine the relationship between speeds in school zones and school speed limits. Spot speed data were collected in school zones with school speed limits from 15 to 25 mph. Multiple regression analysis of the data indicated that speeds in the school zones were influenced more by the speed characteristics and limits of the streets on which the zones were located than by the school zone speed limits. Also, on streets with normal speed limits of 35 mph, the 85th percentile speeds in zones with 25-mph school speed limits were lower than those in zones with 15-or 20-mph limits. Therefore, it was concluded that school speed limits lower than 25 mph should probably not be used on these streets.

Previous studies (1, 2) have found no relationship between pedestrian accident experience and school zone speed limits. However, speed limits in school zones are sometimes established in response to the public perception that lower speed limits are a prime factor in school zone safety. Although drivers may acknowledge the lower speed limits as being safe, several studies have found driver compliance with school speed limits to be poor (3, 4)-less than 20 percent. In many cases, the 85th percentile speed was more than 20 mph above the school speed limit. Attempts to increase driver compliance by improved signing and stepped-up enforcement have provided only slight increases in compliance and modest reductions in speed (5-8). The lack of compliance may cause such speed control efforts to be counterproductive. Therefore, researchers (3) have concluded that the safety of a school zone requires not only the use of effective signing and strict enforcement, but also the establishment of reasonable school zone speed limits.