Washington, D.C. has a maximum speed limit of 55 mph (89 km/h). On all streets and highways, unless otherwise designated, the maximum lawful speed is 25 mph (40 km/h). In alleys, the maximum speed limit is 15 mph (24 km/h). Regardless of the posted speed limits, no driver shall drive a vehicle at a speed greater than is reasonable and prudent under the conditions, and having regard to actual and potential hazards.
On all streets adjacent to school buildings and grounds, the maximum speed limit is 15 mph (24 km/h) at the times indicated on official signs. When no times are indicated on official signs, the maximum speed limit shall be 15 mph (24 km/h) during recess periods or while children are arriving and leaving during school opening or closing hours. On all streets adjacent to playgrounds designated by official signs, provided the playground is in use, the maximum speed limit is 15 mph (24 km/h).