The school plate is black and yellow and the speed limit is black and white. The signs are installed by the appropriate governing authority. These black and orange signs are used in advance of work areas. Temporary construction zone speed limits are regulatory speed limits established for long term construction projects or detour routes. These black and white signs are used when a reduced speed is needed for driver safety.
Studies show that there is little change in the speed pattern after the posting of a speed limit.
The driver is much more influenced by the roadway conditions. Although lowering the speed limit is often seen as a cure-all in preventing accidents, this is not the case. Accidents are most often the result of driver inattention and driver error. This speed variance can contribute to accidents. A uniform speed of vehicles in a traffic flow results in the safest operation.