Use freeways whenever you can. Studies have shown that stop signs, red lights and stop-and-go traffic consume fuel more than almost any other negative factor or bad habit. So head for the freeway and stay on it until you have to make a delivery or take a rest.
Get moving shortly after cranking over the engine, and shut it off as soon as you're parked. A modern diesel (and even most old ones) need only a few minutes to warm up, and the temperature will come up as you leave the yard and wait at lights to get to the road. A hot engine and its turbocharger will likewise cool down during similar pauses. You can almost always limit warm ups and cool downs to five minutes.
Avoid idling the engine. Turn it off whenever you can, such as while sitting at long red lights (you know where they are if you're on a regular route), waiting for long freight trains, and especially while waiting to load or unload. Always turn off the engine when you stop to use a phone or go in for lunch. The cab will cool off or warm up again within minutes of your return, and while it's doing so, you can do a walk-around inspection. In hot weather, idle to run the air conditioner, but only when you really need to.
"Short shift." When starting out, upshift at low rpm in low-range gears, gradually increasing revs as road speed increases. For example, if the engine idles at 600 rpm, gently engage the clutch, let the truck start moving, then apply a little gas. Shift to second at 1,000; to third at 1,100; to fourth at 1,200 and so on. This can be done because you don't need the horsepower produced at higher revs until the truck approaches highway speeds.
Let momentum move you. Get off the gas before you approach a speed zone and are about to enter a small town, and downshift only enough to avoid bogging down the engine. Then watch as the truck drifts for blocks with no power application. Traffic can spoil this tactic, but practice it when you can.
Play with traffic lights. Approach red lights slowly and try to time your arrival at the intersections just before the light turns to green. That saves you a stop and allows you to keep moving more or less steadily.
Plan ahead on upgrades. Avoid storming a hill at the highest possible speed, and instead estimate the final gear you'll need to top it. Get into that gear early and stay there, and feed the engine only the fuel it needs to sustain a speed in that gear. Then, ease off the gas as you approach the hill's crest. Upshift just before you reach the top; then stay off the gas and let the truck's momentum carry you over.
Cruise in the engine's "sweet spot." The point where power and economy are highest is around 1,450 rpm in many of today's heavy diesels and about 1,600 rpm in those made in the late '90s and early '00s. Smaller engines have sweet spots, too. Find out where they are from published information from engine builders, and cruise down the highway at that engine speed.
Use cruise control. Many engines are set up to deliver more power and torque when CC is engaged, so use it.
Let gravity do the work. As you begin rolling downhill, leave the accelerator alone. Gravity will increase the truck's speed unless it's a shallow grade or you're heading into a strong head wind. In those cases, use only the minimum amount of power to return to a sensible cruising speed. Skip-shift as speed climbs, but let revs go up if you'll need the engine brake to control your downhill speed.
Don't overuse the engine brake. Trying to downshift too frequently to get maximum retarding power will often result in your going faster than you should, and you'll be a safety hazard and burn more fuel. You also risk missing a downshift and being stuck in neutral with no retarding power at all. A combination of the engine brake and gentle applications of service brakes will be smoother and cause little lining wear.
Word from a Wise (Older) Guy
Owner-operators stand to save the most from economical driving habits because they have to buy their own fuel. But many don't bother to save because they like to run with their buddies and are otherwise caught up in the "fun" of the business. Yet sometimes the older and wiser guys realize that trucking is a living more than a game.
Mark Allen, 42, of Romoland, Calif., is an example. He says his stingy habits get him about 6.7 miles per gallon with his 80,000-pound transfer dump when other guys get 4, 5 and 6 mpg.
"I get a lot of ribbing because I don't drive the same thing they do and don't drive like a lot of them do," says Allen, who's been truckin' since his teenage days, when his father owned and operated dump trucks. He also studied diesel mechanics at a trade school in Phoenix, has considerable fix-it skills, and most of all, a mind of his own.
"I run this '89 Freightliner with a setback axle, and that's not too common," as most truckers in southern California prefer "large cars" with forward-set steer axles. The Freightliner was a road tractor with a big sleeper box, which Allen had removed when he decided to switch from flatbed hauling of building supplies to dump trucking. He shortened the wheelbase, installed an 15-foot box and the hookups to pull a transfer-dump trailer.
With a transfer rig, the truck itself never hauls more than half its total load, as it dumps the truck's load first, then shoulders the trailer's box and goes to dump it; so the ex-tractor is not unduly strained. And its setback steer axle lets Allen make tight U-turns where others can't. This helps on asphalt paving jobs, which is most of his business. He doesn't know if the FLD 120's aerodynamic nose gets him better fuel economy, but it doesn't hurt when he encounters head- and sidewinds.
Driving conservatively is his other main way to save fuel. He keeps revs of his Caterpillar 3406B low—1,700 rpm is about tops—because lower engine speed saves fuel. "My mechanic has it set up just right, so it pulls from way down. I've got a buddy who's got the same kind of Cat, but his is set up differently; he's got a 1,700-and-up engine and mine is a 1,700-and-down."
Still, Allen likes power. The mechanically controlled 3406B started life making 400 horsepower, "but it's set up way higher now. I don't even know where it's at, but I can climb long hills much better than most guys." On longer runs he likes