Trucks are made to be in motion. When efficiency is judged by MPG, the truck’s worst fuel efficiency is when the truck sits still. Idling burns fuel and can lead to increased maintenance issues. That’s why a number of idle reduction solutions are gaining ground with fleet managers aiming to lower diesel usage costs and still provide the necessary truck heating, cooling and power requirements.

Diesel APUs

Yes, you’re still using diesel fuel to power the idle truck and it requires maintenance like any diesel engine, but a diesel-powered auxiliary power unit (APU) provides huge fuel savings over running the tractor engine. As the overall efficiency of tractors and trailers moves forward, there’s a new twist in the APU value proposition—driver retention.

The latest numbers from the , which uses driver turnover as a barometer of the driver shortage, showed that truckload characters turnover was 95%, down one percentage point from 2013, but turnover at small fleets was 90%—up 11 points from the year before. The five point gap between the two turnover rates is the smallest since 2000.

“These figures show us that the driver shortage—which we now estimate to be between 35,000 to 40,000 drivers—is getting more pervasive in the truckload sector,” said ATA Chief Economist Bob Costello. “Due to growing freight volumes, regulatory pressures and normal attrition, we expect the problem to get worse in the near term as the industry works to find solutions to the shortage.

While keeping an eye on the idle cost bottom line, fleet managers can also help their operations improve their driver retention numbers by spec’ing equipment that keeps the truck’s amenities going during idle time. Enter the APU.

“Historically, the value proposition of an APU was entirely around fuel savings. Today, it’s less dependent on fuel savings and more focused on driver comfort, driver retention and driver recruitment,” said Steve DeLarosby, product manager of APUs and Heaters, Thermo King, which offers its TriPac Evolution APU. “Fleets that have APUs are finding huge savings by improving overall employee retention and reducing driver recruiting efforts and the training costs that come with new drivers. APUs are one of the best recruiting tools for keeping drivers happy with their employment and preventing them from moving around from company to company.”

There’s still a savings associated with running APUs. Joe Yoder, director of sales and marketing for the Fort Worth, Texas-based Cantwell Power Solutions, a Dynasys APU dealer, said that typical truck engines consume around a gallon of diesel per hour depending on engine size and RPMs. Most diesel APUs burn around one quart per hour. With $3/gal. diesel, that amounts to $0.75 per hour or $7.50 for 10 hours. Nevertheless, Yoder also highlighted the driver retention APU benefits.

“An APU’s No. 1 goal is to make drivers more comfortable and give them complete control over their environment,” Yoder explained. “The new units are considerably quieter than older models, and that promotes better sleep. Some models, like the Dynasys, will even switch automatically between heating and air conditioning if the outside temperature changes dramatically. The Dynasys also comes with a date and time calendar. This means that, if the truck sits while the driver’s on vacation, the APU can be programmed to start two hours before the driver returns. The cabin is cool or warm depending on the time of year, the engine has been pre-warmed, and the batteries are at peak capacity.”

Another major factor of savings comes from reduced tractor engine wear.

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