Idle Reduction Requirement

A motor vehicle engine may not operate for more than five consecutive minutes when the vehicle is not in motion, with the following exceptions: 1) when traffic conditions or mechanical difficulties do not allow the vehicle to operate; 2) when it is necessary to operate heating, cooling or auxiliary equipment installed on the vehicle; 3) to bring vehicle to manufacturer’s recommended operating temperature; or 4) if idling is necessary to accomplish the intended use of the vehicle.

(Reference Maryland Statutes, Transportation Code 22-402)