Regulatory speed zones should be applied only to those locations and sections of highways which are not dealt with adequately by the general statewide speed limits, and they should be indicators of the speed limitations imposed by physical and traffic conditions at such locations. Speed limits are determined by specific roadway and traffic conditions. Speed limits should not be lowered to the extent necessary for a driver to avoid a collision with a pedestrian or other motorist who is entering or crossing the highway in violation of an existing traffic regulation.

Roadway safety is an important consideration in establishing speed limits. The following factors affect roadway safety and, therefore, should be considered when establishing speed limits: