Maricopa County, AZ Environmental Rules: Vehicle Idling Restrictions (2026)
Key Facts
- Idle time limit
- 5 consecutive minutes
- Applies to
- Diesel vehicles over 14,000 lbs GVWR
- First offense fine
- $100 civil penalty
- Repeat offense fine
- $300 civil penalty
- Sign requirement
- 12x18 inch sign at truck stops
Summary
Diesel trucks over 14,000 pounds are barred from idling more than five consecutive minutes anywhere in Maricopa County, with $100 first-offense and $300 repeat civil penalties under Ordinance P-21.
No owner or operator of a vehicle shall permit the engine of such vehicle to idle for more than five (5) consecutive minutes except as provided in Section 4 (Exemptions) of this ordinance. ... Any owner or operator who violates this ordinance is subject to a civil penalty of $100 for the first violation and $300 for a second or any subsequent violation.
Full Breakdown
Ordinance P-21 restricts idling of diesel-powered vehicles with a gross vehicle weight rating over 14,000 pounds, registered for public highway use, to five consecutive minutes anywhere in the county. Owners and operators face a $100 civil penalty for a first violation and $300 for each later one. Truck stops and distribution centers must post a permanent 12-by-18-inch sign stating the five-minute limit, the fine, and the county's idling information line. Exemptions cover traffic or weather delays, emergency vehicles, power-take-off mechanical operations, manufacturer warm-up and cool-down, passenger comfort up to 30 minutes per hour, and federal hours-of-service compliance.
Violations & Fines
$100 civil penalty for a first offense, $300 for each subsequent violation; enforceable by any law enforcement officer on public or private property under ARS 11-876.
Frequently Asked Questions
Does the 5-minute idling limit apply to my car?
Can a bus idle to keep passengers warm or cool?
Is the idling limit only for unincorporated areas?
Sources & Official References
Other rules in Maricopa County
Compare Maricopa County to another location·View the Arizona environmental rules overview
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