Can the speed limit be lowered on a particular street?
In residential areas, the speed limit is set at 25 mph by the California Vehicle Code. On non-residential streets, the speed limit is set based on a radar survey. The standards for setting speed limits are set forth in the California Motor Vehicle Code. Therefore, a speed limit is not just arbitrarily set but based on the actual speeds of vehicles. Lowering a speed limit in hopes of seeing a correspondent slowing of traffic does not usually work. Setting a speed limit without following the Vehicle Code guidelines would invalidate any citation issued by use of radar.
