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 crashes, this is not the case.
Crashes are most often the result of driver inattention and driver error.
This speed variance can contribute to crashes. A uniform speed of vehicles in a traffic flow results in the safest operation. The posted speed limits can keep the traffic flowing smoothly provided the majority of drivers find the speed limits reasonable. To best do this, the limits must be consistent throughout the state. The speed limits also give the motorist an idea of a reasonable speed to drive in an unfamiliar location.