All states, including the District of Columbia, formulate their speed regulations on the basis of some form of the basic speed law. This law specifies that a driver shall operate a vehicle at a speed that is reasonable and prudent for existing conditions, regardless of any other speed limit that may be applicable at a location at any given time. 

A driver is responsible for taking both actual and potential hazards into consideration when selecting a speed and for giving due regard to weather, visibility, traffic, roadway width, and condition.