The American Trucking Associations (ATA) estimates the current shortage of drivers is roughly 35,000 to 40,000. The inability to find new drivers is a reality that many fleets face today, and it is only expected to continue. Due to the industry’s aging workforce, ATA estimates trucking companies will need to recruit nearly 100,000 new drivers a year over the next decade in order to manage the country’s freight needs.

Retaining drivers also has become an issue for fleets. According to the ATA, the national driver turnover rate was 84% in the first quarter of 2015—the first time it fell below 90% since 2011. ATA’s Chief Economist Bob Costello attributes part of this drop to improved retention efforts of fleets across the board.

An effective driver retention effort is an anti-idling option. It’s a driver’s market and fleets can no longer expect drivers to accept a job that prohibits idling of a tractor engine. Whether it is to stay cool in the summer heat or keep warm in the dead of winter, idling to maintain a comfortable state is a significant factor when you consider mandatory rest due to hours of service regulations. However, fleets know that idling is a burden to the bottom line—trucks get the worst fuel efficiency when sitting still, as idling not only burns fuel, but leads to increased maintenance intervals. Fleets need to provide drivers with the ability to maintain their wanted comfort level on the road while also ensuring resources are being used wisely. That’s where the auxiliary power unit (APU) comes in.

An APU is a small diesel engine or battery power pack that provides power for a range of uses on a truck. Without idling the truck’s main engines, an APU can provide heating and cooling to maintain a comfortable temperature in the cab and sleeper, as well as power laptops, gaming machines, microwaves, and even continuous positive airway pressure (CPAP) machines.

Aside from simply keeping drivers comfortable and allowing them to control their own environment, APUs allow fleets to reap the benefits in reduced fuel costs. By decreasing the amount of hours a truck idles, fleets can save as much as $140 per week, per truck—depending on fuel costs and idle time—in the experience of Thermo King, a manufacturer of temperature control systems for various mobile applications and a brand of Ingersoll Rand. Fleets also realize the benefits of an APU when they are ready to sell the tractor, due to the reduction of overall idle hours on the engine, which improves the resale value of the tractor.

An APU’s value was once seen solely by the amount of fuel it saved. Now, its value is less dependent on fuel savings—although still a factor—and more focused on the driver, and their overall experience while on the road. Operationally, the most advanced APU solutions provide significant fuel-saving advantages compared to generator-based designs. With today’s fuel prices, which have dropped considerably over the past year, Thermo King still estimates when factoring in four components—fuel savings, driver retention and reduction in training costs, tractor maintenance, and increase in resale value—certain APUs have a 12-month return on investment.

Fleets that use APUs continue to see huge savings by increasing employee retention, and reducing driver recruiting efforts along with the immense training costs that come with new drivers. With the industry outlook estimating 1 million new drivers will be needed over the next decade, APUs will continue to be one of the best solutions for not only recruiting new drivers, but keeping fleets’ current drivers happy so fleet managers don’t continually face the same recruitment dilemma year after year.

Steve DeLarosby, Product Manager of APUs and Heaters, Thermo King, wrote this article for SAE Magazines.