The trucking industry is doing an amazing job of improving the fuel efficiency and reducing the carbon emissions of the vehicles used to transport the nation’s freight. Some is driven by saving money on fuel, some is driven by sustainability goals, some is driven by government regulations.

However, in the pursuit of fuel efficiency, sometimes regulations, truck specs and changing operations can end up costing you money in other areas.

Most obvious, of course, is the increased up-front cost of trucks that meet the government’s latest fuel economy regulations. Or the up-front cost of items such as trailer skirts, auxiliary power units and other devices. Then there’s the cost of maintaining those systems.

Other “unintended consequences” of fuel-saving strategies are not so obvious.

For instance, take the trend toward fuel-saving “downspeeding” of engines, with highway cruise rpms of 1,300 and less. This requires extra torque to compensate for the loss of horsepower, and that can damage driveline components, a panel of experts said during a session at the fall TMC meeting. “Fast” axle ratios further slow the driveline, exacerbating the problem, they said.

Or consider the simple practice of turning your engine off every time you stop the truck.

In stop-and-start operation where the engine is turned off during deliveries, for instance, Chevron-commissioned testing by the Southwest Research Institute showed that when the engine was turned back on after 8 minutes, the turbocharger oil temperature spiked by 67 degrees. This is called heat-loading, and it can shorten the life of your engine oil, your turbocharger and your engine.

Increased “costs” aren’t only limited to your bottom line. They can be environmental and societal as well.

For instance, back to the regulatory front, we’re seeing a potential conflict on emissions between the Environmental Protection Agency and the California Air Resources Board. The EPA is writing its next-generation rule on fuel economy and greenhouse gas emissions. Meanwhile, CARB is still fixated on NOx.

Amy Kopin, senior compliance engineer at Detroit Diesel, pointed out in another TMC session that as fuel economy increases and CO2 decreases, NOx rises. So the CARB proposals run counter to EPA’s demands to reduce CO2.

And on the federal front, back in 2010, the National Academies of Science published a report looking at the issue of government fuel economy standards for medium and heavy trucks. It noted at the time that there were some other approaches that could be more effective and less costly, including driver training, raising fuel taxes to act as an extra incentive for fleets to cut fuel use, and increasing vehicle size and weight limits.

Don’t hold your breath waiting for those second two options.

So what does all this mean?

Keep up the good work on cutting fuel use, but make sure to do your homework. I’m confident that smart fleets and the engineers at the truck makers will educate themselves on some of these potential consequences, and continue an impressive march toward ever more fuel-efficient, cleaner and greener trucks.

The regulatory folks may need some help.