Maryland Truck Idling Law
Maryland caps idling at 5 consecutive minutes when a truck is not moving (Transportation 22-402(c)(3)). The exemption for running heat, AC, or auxiliary equipment on the vehicle effectively covers APUs and cold-weather use. The preset first-offense fine is about $70; repeats can be taken to court, where the penalty runs higher.
Some figures on this page are flagged medium confidence. The limit and source are solid, but a specific fine or local detail should be confirmed with the state agency before you rely on it.
When you can keep idling
- Traffic or mechanical trouble
- Heat, AC, or auxiliary equipment on the vehicle
- Reaching operating temperature
- PTO and intended use
APUs and idle-reduction gear
Heating, cooling, and auxiliary-equipment idling is exempt, which covers APUs. Idle-reduction tech earns up to a 550-pound weight allowance.
City and county ordinances
- Montgomery County applies the statute and treats cold-weather heat (below 40F) as covered by the heating-equipment exemption.
Maryland Idling Law FAQ
Is there a truck idling law in Maryland?
How long can a truck idle in Maryland?
What is the fine for idling in Maryland?
Does an APU count as idling in Maryland?
Reference information for planning, not legal advice. Traffic laws change and this can be out of date, so always confirm the current statute and obey posted signs before you rely on it. Last reviewed July 2026. Source: https://afdc.energy.gov/fuels/laws/IR?state=MD. See our Terms & Disclaimer.
More for Maryland
Check Maryland before you roll
Live weather, closures, and hazards on one map. Free, no account.
Open Live Map →