This page last reviewed  March 11, 2009

Pursuant to state regulation, operators of diesel-fueled trucks, with a gross vehicle weight rating greater than 10,000 pounds, shall not idle for more than 5 minutes when stopped within California's borders. As of JANUARY 1, 2008, this restriction also applies to sleeper berth trucks. Consequently, many operators are now required to use some form of idle reduction technology to provide cab comfort services during periods of sleep and rest. To assist operators who may not be familiar with idle reduction technologies, ARB has developed this webpage to provide general information regarding various technologies that are currently available.

All idle reduction alternatives presented here require some amount of out-of-pocket expense. However, it is expected that operators will recover their costs over time through fuel and maintenance savings. ARB estimates that cost recovery times will range between 8 months and 3 years, but actual recovery times will depend on the equipment selected and the amount of time spent at idle.

In the spirit of air pollution prevention, ARB encourages the use of zero- and low-emissions technologies such as battery-powered systems, thermal energy storage systems, and truck-stop electrification systems. Selecting certain zero-emissions technologies may also qualify you for financial incentives through California's Carl Moyer Program. Please visit the program webpage or contact your local air district for details.

• Battery-Electric Auxiliary Power Systems

  Using advanced battery packs, battery-electric auxiliary power systems provide heating, cooling, and electrical power to ancillary cab appliances. These systems are designed so that the primary engine charges the batteries during normal road operation. However, certain systems equipped with the capability to "plug in" also allow operators to use shore power to charge the battery and/or power the system. The battery packs require approximately 2-6 hours of charge time and can run the air conditioning system for up to 12 hours per full charge. The option to "plug in" is available at participating layover locations.

• Vehicle-Battery Systems

  Vehicle-battery systems are less expensive alternatives more commonly used in day cab applications. Currently, vehicle-battery systems on the market offer either cab heating or cab cooling, but not both. Some examples of vehicle-battery systems include heated coolant recirculation systems, evaporative cooling systems, and window fans. Although these systems typically offer limited services, they can be paired with other devices. For example, pairing an evaporative cooling system with a fuel-fired heater can provide a more complete climate control package.

• Truck Stop Electrification (On-Board Power Infrastructure)

  By installing on-board electrical hardware and an electrically-powered climate control system, drivers can "plug in" their vehicles and draw electricity directly from the power grid. The electricity can be used to provide cab heating and cab cooling, to power cab appliances, and to charge the vehicle's battery. Access to the grid is achieved through outlet pedestals installed at participating layover locations.

• Truck Stop Electrification (Off-Board Power Infrastructure)

  For an hourly fee, providers may offer heating, cooling, television service, telephone service, and internet service through a duct that attaches to the vehicle through an adapter (one-time purchase) fitted into the vehicle's side window opening. Electrical outlets are also provided for powering ancillary cab appliances such as microwaves and televisions. Since direct heating and cooling are provided, vehicle operators can avoid the costs of purchasing and installing on-board electrical and climate control equipment. Service is available at participating layover locations.

• Thermal Energy Storage Systems

  A Thermal energy storage system stores cooling energy from the vehicle's air conditioning system during normal road operation. The stored energy can be used to cool the cab at a later time when the engine is off. This system only provides cooling, but can be paired with a fuel-fired heater for a more complete heating and cooling package.

• Diesel-Fueled Auxiliary Power Systems

  Diesel-fueled auxiliary power systems use small diesel engines to generate power for cab heating, cab cooling, and operating ancillary cab appliances. These units can also be used to heat the engine block in cold weather and recharge the vehicle's battery. Because of the engine's smaller size, operating a diesel-fueled auxiliary power system uses only a fraction of the fuel that would be used by idling the vehicle's primary engine

  Note: For trucks with 2007 and newer model year engines, additional requirements apply. Please see "approved and verified equipment" below for a list of diesel-fueled auxiliary power systems approved for use on these vehicles. For trucks with 2006 and earlier model year engines, any California- or federally-certified internal-combustion auxiliary power system may be used.

• Fuel-Fired Heaters (Fuel Operated Heaters)

  Fuel-fired heaters provide heat to the cab and the engine block, and use only a fraction of the fuel that would be used by idling the vehicle's primary engine. They can also be paired with other cooling technologies for a more complete heating and cooling package.

  Note: For trucks with 2007 and newer model year engines, additional requirements apply. Please see "approved and verified equipment" below for list of fuel-fired heaters approved for use on these vehicles.

Note: ARB does not endorse the purchase or use of products and/or services from any specific vendor/provider and makes no claims as to the effectiveness or operation of these products and services. Furthermore, determining the suitability of any specific cab comfort system and its legal use within California is the sole responsibility of the purchaser/operator. Please see ARB's Conditions of Use document for additional conditions pertaining to the use of ARB's website.

Additional requirements apply to diesel-fueled auxiliary power systems and fuel-fired heaters operated on diesel-fueled trucks equipped with 2007 and newer model year engines. The requirements are as follows:

• Diesel-Fueled Auxiliary Power Systems:
  • A diesel-fueled auxiliary power system operated on a truck equipped with a 2007 or newer engine must:
  • Be fitted with a verified Level 3 particulate control device (85% particulate reduction efficiency), or
  • Have its exhaust plumbed into the vehicle's exhaust system upstream of the particulate matter aftertreatment device.
  • In addition, an approved "Verified Clean APS" label must be affixed to the hood of the vehicle.
• Fuel-Fired Heaters (Fuel-Operated Heaters) operated on trucks equipped with 2007 and newer engines must meet emission standards specified in California's Low Emission Vehicle Program.

For a list of diesel-fueled auxiliary power systems approved for use on trucks equipped with 2007 and newer engines, please see "approved and verified equipment" below. For trucks with 2006 and earlier model year engines, any California- or federally-certified internal-combustion auxiliary power system may be used.

For a list of fuel-fired heaters approved for use on trucks equipped with 2007 and newer engines, please see "approved and verified equipment" below. For trucks equipped with 2006 and earlier model year engines, any fuel-fired heater may be used.

Please contact manufacturer for additional information regarding approved and verified devices

• Verified Level 3 Particulate Matter Control Devices for use on diesel-fueled auxiliary power systems
• Teleflex Ecotrans Technologies' Clear Sky Diesel Particulate Filter for use with Comfort Pro auxiliary power systems equipped with a model year 2005 through 2008 Kubota Z482 engine.
• Thermo King's Electric Regenerative Diesel Particulate Filter for use with TriPac auxiliary power systems equipped with model year 2006 through 2009 Yanmar TK270M engine.
• Diesel-Fueled Auxiliary Power Systems approved for use on trucks equipped with 2007 and newer engines.
• Cummins' integrated diesel-fueled auxiliary power system (only compatible with 2008 and 2009 model year ISX engines)
• Fuel-Fired Heaters (Fuel-Operated Heaters) approved for use on trucks equipped with 2007 and newer engines.
• Espar Airtronic D2
• Espar Airtronic D4
• Espar Hydronic 5
• Webasto Air Top 2000S
• Webasto Air Top 2000ST
• Webasto Thermo Top C / TSL 17

• ARB's Commericial Idling Regulation Webpage
  

  Find the text of the idling regulation, fact sheets, and other useful information.

• Carl Moyer Financial Incentives Program

  Find information regarding California's Carl Moyer Financial Incentives Program.

• United States Environmental Protection Agency's Idling Reduction Technology Webpage
  

  Find information on idle reduction technologies and the Environmental Protection Agency's Smartway Program.  Please note that ARB does not maintain this website and is not responsible for its content.

• United States Environmental Protection Agency's Webpage Concerning a Federal Excise Tax Exemption Available for Certain Idle Reduction Technologies

  Find information on a recent amendment to the United States Internal Revenue Code that exempts certain idle reduction devices from federal excise tax.  Please note that ARB does not maintain this website and is not responsible for its content.

• United States Environmental Protection Agency's SmartWay^(SM) Finance Center Webpage
  

  Find information on financing that is available for purchasing cleaner trucks and trailers, and emissions-reducing and fuel-saving technologies (such as auxiliary power systems)  Please note that ARB does not maintain this website and is not responsible for its content.

• Cascade Sierra Solutions' Driver Assistance Webpage
  
  Cascade Sierra Solutions is a non-profit organization established to help truckers finance and install fuel-saving and emissions-reducing devices on their trucks.  Please note that Cascade Sierra Solutions is not affiliated with ARB, and ARB is not responsible for any information, products, and/or services obtained through their website or their organization.

• For questions or comments, please contact David Chen at (626) 575-6673 or dchen@arb.ca.gov.