Diesel Idling
Search Air Quality Web Site
CLEAN AIR MAKE MORE

Diesel Idling

Consequences of Diesel Idling



Idling Consumes Fuel and Adds to Truck Maintenance Costs


Trucks idle 40 - 60% of their working life. Nationally, they burn 4 billion gallons of fuel each year when idling, going nowhere. Idling increases engine maintenance costs and shortens engine life.


Global Warming


CO2 (carbon dioxide) is also produced by diesel engine idling. Carbon dioxide is widely accepted as a significant contributor to the greenhouse effect and climate change.


Health Impacts of Diesel Emissions


Diesel exhaust particulate matter is a toxic air contaminant. Diesel engines contribute to fine particulate matter (PM2.5) air quality problems. Children, whose lungs are still developing, and the elderly, who may have other serious health problems, are the most vulnerable to PM2.5 air pollution.



Maricopa County Vehicle Idling Restriction Ordinance



The purpose of ordinance P-21 is to protect public health and the environment by reducing emissions of toxics and criteria pollutants while also conserving fuel. Affected vehicles are required to limit idling to no longer than five minutes under most circumstances.


Vehicles Affected by the Ordinance


The ordinance applies to diesel-fueled commercial motor vehicles that weigh more than 14,000 pounds operating in Maricopa County, regardless of where the vehicles are registered. It applies to vehicles designed to operate on public highways and powered by a diesel engine.


Penalties for Non-Compliance


The driver of the vehicle who violates this ordinance is subject to a minimum civil penalty of $100 for the first violation and $300 for a second or any subsequent violation.


Exceptions to the Idling Restrictions


  • Drivers stuck in traffic due to congestion or weather issues.
  • The main engine is being idled during DOT mandated rest periods (US 49 CFR Part 395, AZ R17-5-202).
  • The main engine is being idled in order to conform to the manufacturer's "warm up" or "cool down" specifications.
  • The main engine is being idled for maintenance or diagnostic purposes.
  • The main engine meets ALL of the following:
    • Provides a necessary power source for mechanical operations other than propulsion
    • Involves a Power-Take-Off (PTO) mechanism
    • Powers the loading/unloading of cargo, the mixing or processing of cargo, the temperature control of cargo, or a mechanical extension to perform work functions
  • Passenger buses (including school buses), which are being idled in order to provide heat or air conditioning necessary for comfort/safety may idle for up to:
    • 30 minutes during any 60 minute period
    • When temperatures exceed 75 degrees Fahrenheit, allowed to idle up to 60 minutes during any 90 minute period
    • Or for Emergency and/or law enforcement purposes


Idle Control Programs / Technologies



Reduction Technologies for Trucks


A large amount of truck idling occurs at travel centers while truckers rest during layover periods. Engines are idled to maintain comfortable temperatures while resting or to provide power for televisions, refrigerators, microwaves, etc. Technologies are available that can provide for these needs without engine idling. For example:


  • Automatic Shut-Down/Start - Up Systems - electronic diesel engine shut down after a set time period.
  • Battery - keeps the inside of a vehicle cab warm in the winter or cool in the summer.
  • Auxiliary Power Unit or Generator Set - provides heat and air conditioning for the cab.
  • Electrified Parking Spaces - Electric shore power connectivity can provide heat, air conditioning, and electrical power.


SmartWay Transport Partnership with the EPA



Truck technologies that save fuel or use fuel more efficiently can pay for themselves through fuel savings. The EPA SmartWay calculator helps truck owners and fleet owners compare the costs and estimate the fuel savings associated with various efficiency technologies.



Reduction Technologies for Trucks


A large amount of truck idling occurs at travel centers while truckers rest during layover periods. Engines are idled to maintain comfortable temperatures while resting or to provide power for televisions, refrigerators, microwaves, etc. Technologies are available that can provide for these needs without engine idling. For example:



How to Report Diesel Idling Violations



You may use any of the following options to report a suspected idling violation:

  • Call the Maricopa County Air Quality Department at (602) 372-2703.
  • Report an air quality violation online.