Taking the Driver Out of the Fuel Economy Equation

While spec'ing aerodynamic devices, low roll-resistant tires, automatic engine shutdown, speed limiters and the such can go a long way to lower your fuel bill, the biggest factor in fuel economy is still the driver and driving for optimum fuel economy is becoming an increasingly daunting proposition and driver training is becoming more critical.

A few simple changes in driving techniques can produce sizable fuel savings of 5% or more. A Canadian study estimates that many fleets could achieve a 10% fuel economy improvement through driver training and monitoring. For a typical combination truck, a 10% saving is the equivalent of nearly $2,500. A study for the European Commission estimates that an annual one-day driver-training course will improve truck fuel efficiency by 5%. Two trucking fleets in Canada documented the impact of driver training and found fuel efficiency improvements of 18% and 20%, according to the EPA's SmartWay program. Well-trained drivers can reduce fuel consumption by applying a number of simple techniques. These include: use cruise control where appropriate; coast whenever possible; block-shift (go from, for example, 2nd gear to 5th gear); brake and accelerate smoothly and gradually; progressive shift (upshift at the lowest rpm possible); limit unnecessary truck idling; start out in a gear that doesn't require using the throttle when releasing the clutch; limit unnecessary shifting; drive at the lowest engine speed possible; reduce parasitic energy losses by limiting the use of accessories.

Progressive shifting is still the best way to achieve optimum fuel economy, but as engines continue to evolve to reach ever-more stringent emissions regulations, driving techniques have changed. Even the most experienced drivers will find it difficult to stay in the "sweet spot" where the engine is using the least amount of fuel. Even for the most seasoned pros, if you drive the same way you did in 1990, you're wasting a significant amount of fuel.

Key to driving for fuel savings is education. Engine and transmission OEs can provide information on how to best drive particular engines and transmission combinations for optimum fuel economy and offer training help to carriers.

Transmission manufacturers collaborate closely with all engine manufacturers to develop the best shift patterns for fuel economy for particular engine fuel curves. The best drivers can still use progressive shifting to achieve the best fuel economy, and some of them are amazing at how well they can utilize shifting to optimize fuel economy. But for most, automatic transmissions and sophisticated, integrated power trains make it easier for more fleets to achieve good fuel efficiency.

Through the economic downturn, there are many more non-traditional drivers entering the industry people who have lost jobs in other industries and didn't initially consider becoming a truck driver. Using automated or automatic transmissions can soften the entry of new drivers and lessen the need for extensive driver training. Automation also offers safety improvements. Drivers who are inexperienced can focus more on the job at hand, maneuvering the truck down the highway rather than having to focus on shifting.

While most fleets have steered clear of automatic or automated transmissions in the past, they are becoming increasingly more popular.

One of the country's most progressive truckload carriers, U.S. Xpress, specs automated manual transmissions, which will soon be on 100% of the company's trucks. With automated transmissions, trucks run in a much tighter range and in an optimal fuel curve, company chairman Max Fuller says. They also prevent aggressive drivers from shifting into higher gears too fast. "With good drivers, we don't see much improvement in fuel economy with automated transmissions, but with bad drivers there's significant improvement," Fuller says.

Although fleets may be leery of spec'ing automatic trannies because of the initial upfront costs, the cost per mile because of improvements in fuel economy averages and safety will reduce overall life cycle costs.