Driving of motor vehicles - District of Columbia

Federal regulations

District of Columbia has adopted Part 392 of the Federal Regulations.

Applicability

Part 392 applies to vehicles with a gross vehicle weight rating or gross combination weight rating exceeding 10,000 pounds, and to any vehicle transporting hazardous materials requiring placards.

Engine idling

A gasoline or diesel powered motor vehicle on public or private space may not idle for more than three minutes while the motor vehicle is parked, stopped, or standing.

Exceptions — A vehicle may idle for up to five minutes to operate heating equipment when the ambient air temperature is 32°F or below. There are also exceptions for operating power takeoff equipment including dumping, cement mixers, refrigeration systems, content delivery, winches, or shredders as well as private passenger vehicles.

Speed limit

The speed limit is 55 mph on all highways unless otherwise posted.