Vehicle Idling Reduction Strategies

For most on-road, heavy-duty fleets, idling can account for more than 50 percent of total trip time. The amount of diesel fuel burned, the emissions produced, and the maintenance impacts to trucks owners are significant. Consider the following:

• A class 8 truck typically idles 8 hours per night, 300 nights per year (2,400 hours per year).
• Each year a truck emits over 0.3 tons of nitrogen oxide (NOx) and 21 tons of carbon dioxide (CO2).
• A typical diesel vehicle burns one gallon of fuel for every hour of idling.
• Idling trucks collectively burn away 1.2 billion gallons of diesel fuel annually at a cost of more than one trillion dollars to the industry.
• A truck idling for one hour suffers wear and tear equivalent to being driven seven miles. (ATA Technology and Maintenance Council)
• Operating life of engine oil is reduced by 75 percent due to prolonged idling – from 600 engine hours to 150 engine hours.

As indicated above, idling time can have significant economic impacts, depending on the size of a fleet. For air quality planners, limiting idling time is an understandable target to reduce emissions. For truckers, however, idling is a customary practice due to concerns that restarting the engine will cause damage to the engine. In addition, it is important to be able to operate the truck’s heating and cooling equipment.

Nevertheless, studies on idling practices have found that restarting the engine does not impact the engine as much as assumed. Advances in idling control technologies, specifically auxiliary power units and truck stop electrification, are becoming more appealing to truckers and fleet owners because of cost savings, noise abatement, and improvements in air quality. At the same time, a number of local and state governments have implemented anti-idling legislation and/or ordinances to limit idling in order to address air quality and noise concerns.

Auxiliary Power Units (APUs)

Auxiliary Power Units (APUs) are small, 5-10 horsepower diesel engines that eliminate the need to idle the main engine. While it takes fuel from the same tank as the truck, it has its own internal combustion engine, compressor, and alternator connected to the truck’s operating system to supply direct current power, heating and cooling, electricity to charge truck batteries, and engine warming for cold weather starting. Typically, they consume 80 – 90 percent less fuel than a truck’s diesel engine and provide the same level of heating and cooling comfort for occupants.

In a pilot project with the Department of Energy, APU manufacturer Pony Pack estimates that using these devices could save about $1,600 in fuel costs and $2,000 in maintenance costs annually and can have paybacks as short as one year, depending on the extent of its use.

While they are inexpensive, easy to install, and do not interfere with OEM systems and warranties, APUs may not be a viable option for some truck operators because of their size, weight (300 – 400 lbs.), and maintenance issues.

Auxiliary heating systems specifically for the cab and/or the engine block are many times more efficient than idling. According to the Department of Energy they can run more than 20 hours on one gallon of fuel.

Auxiliary heating, cooling, and/or complete APU systems are readily available and truckers can choose among at least 20 manufacturers located in the United States and Canada. More than 20 percent of Canadian long-haul tractors are estimated to already have APU systems installed on their vehicles.

Truck Stop Electrification (TSE)

When available, electricity is the cheapest form of energy for running a truck’s on-board systems. However, unlike RV parks, marinas, and even airports that provide electricity for mobile users, truck stops do not offer such service. Truck stops are hesitant to install the electrical services because of the costs for equipment and with little demand from fleet owners there is little economic reason to do so.

At the same time, fleets have not had a need to demand electrical service because manufacturers have not installed the necessary equipment on trucks. However, that is beginning to change with fluctuating fuel prices, the need for fleets to stay competitive, and as state and local governments look to cut truck idling as a means to improve air quality. Partnerships between government and industry have already been formed and experts project greater and greater access to electrical service for truckers in the coming years due to the tremendous economic and environmental benefits.

For fleet owners and operators, TSE means fewer oil, cooler, and filter changes that result in lower maintenance costs. At the same time, their equipment goes through less wear and tear equating to longer engine and vehicle life.

An onboard TSE system, which can supply electricity through the inverter/charger to the alternator, battery bank, individual outlets for appliances, and the truck’s operating system range in price from $275 to $2,300, depending on the various features selected. For example a Xantrex Inverter/Charger system’s installed cost is $1,600. Adding on a Domestic (Bergstrom is also building one) AC-powered HVAC system for another $1,200 brings a total system cost of $2,800. Several truck manufacturers, including Volvo and Frieghtliner, are now offering TSE-compatible systems on many of their models.

More advanced TSE systems fit into any truck’s window and provide the driver access to heating, cooling, 100-volt current, phone, cable, and internet access. In the first project in the country to offer this level of TSE, the New York State Thruway has partnered with IdleAire Technologies to install 44 individual electrified parking spaces that offer the service at a cost of $1.40 per hour. The system includes overhead HVAC units controlled by a user panel at the bottom of flexible ductwork where it enters the vehicle. There are currently five TSE systems nationwide.

Advances in Engine Idling Technology

In addition to APUs and TSE, technological advances in diesel truck engines also maximize idling performance. For example, Caterpillar, Inc. offers an “idle shutdown timer” on its electronic engines to help drivers remember not to idle for too long and it can be programmed to turn off the engine after up to 60 minutes of idling. (See the insert on “Advances in Diesel Engine Technology” for more information.)

Policies and Programs

Anti-idling legislation has been enacted in at least 18 states across the country. While some target specific urban areas, state-wide restrictions are in place in Connecticut, Massachusetts, and New Hampshire. Each of these states have anti-idling laws that prohibit idling for more than 5 minutes with exceptions, such as when stopped at a traffic light, operating an APU, unless required by the OEM, during repair, or during very cold temperatures. In Massachusetts, penalties of $100 for the first offense and up to $500 for subsequent offenses are in place.

Idling and smoke emission regulations are in place in 25 states, including Colorado, which has idling restrictions in Denver (10 minutes during any 1-hour period), Aspen, and Colorado Springs.

Sources

Argonne National Laboratory – “Analysis of Technology Options To Reduce the Fuel Consumption of Idling Trucks,” June 2000
Fleet Owner Magazine
U.S. Department of Energy – www.energy.gov
U.S. Environmental Protection Agency – www.epa.gov