RSA are zones with a reduced speed. These can be used to temporarily slow the speed of vehicles traversing sharp turns on ramps or turning movements. A vehicle approaching a RSA decelerates in anticipation of it to reach its temporarily reduced desired speed. The RSA assigns a temporary desired speed to the vehicle, after which the desired speed of the vehicle reverts to the original desired speed set by the last DSD or the global network speed. A RSA only affects vehicles with a desired speed greater than the temporary speed assigned by it. If the desired speed is less than the RSA speed, the vehicle ignores it and continues to operate at the desired speed. RSA can be set for specific vehicle classes.