Most drivers naturally select a comfortable speed, not too slow or too fast, but one that will get them where they want to go safely and without undue delay.
Speed limits are posted primarily to inform motorists of the speed considered reasonable by a majority of drivers on a particular roadway. Motorists, especially those unfamiliar with the road, can use this information to evaluate how they should drive on a particular road. A safer driving environment is established when motorists drive at the same speed.
For more information, contact your local district office.