Whether you’re an owner-operator trying to survive or a company driver going for a fuel bonus, there’s money to be made by improving your efficiency at the wheel.

Fact is, the worst driver will get as much as 35 percent less fuel mileage than the best one, which offers a ton of room for improvement.

But it’s a complex business, figuring out fuel economy, because the variables just never stop mounting up.

Depending on where and what and how he drives, one guy might be deliriously happy to be on the right side of 5 mpg while another would be considering suicide if he dropped below 9.

The only real marker here is your own. So before you launch into a self-improvement program, first determine just where your average fuel mileage sits — for a given run in a given season. Then you can start adjusting how you drive and be able to see what works and what doesn’t.

The following tips, compiled from many sources including Bridgestone, Cummins, Kenworth, Michelin, Volvo and others, will all help to some degree depending on your starting point.

1. Slow down. If you get, say, 7 mpg at 55 mph, then it’ll be 6 mpg at 65 mph. And at 70 mph, you’ll be down to 5.5 mpg. Those are not small differences.

2. Spend as much time as you can — 90 percent or more — in top gear. Don’t get in the habit of cruising one gear down.

3. Assuming the road isn’t slippery, spend as much time as you can in cruise control.

4. Aim for the lowest number of engine revolutions per mile. With every engine out there, you’ll win by cruising below about 1300 rpm.

5. And use the engine’s full operating range before downshifting. All modern engines are happy to pull at 1000 rpm or so.

In rolling terrain, a light throttle is the way to go

6. Try to maintain high average speeds while spending the least time at the truck’s maximum speed.

You can do that in several ways, starting with keeping a high field of vision and staying well back from the vehicle in front of you. That allows you to anticipate changes in traffic and road conditions and lets you avoid rapid deceleration or abrupt stops. You’ll waste fuel getting back up to speed.

7. Try coasting to a stop gradually instead of staying on the loud pedal and then braking hard.

8. Get access to the information in your engine’s black box and analyze the number of sudden decelerations and service-brake actuations you make. Use this info as a benchmark to improve against.

9. Old issue, but you really should minimize the amount of time your engine idles. Every idling hour can decrease fuel efficiency by 1 percent. Sometimes there’s no choice, in which case choose the lowest idle speed possible, like 800 rpm or less.

10. In rolling terrain, a light throttle is the way, and allow momentum to carry the vehicle over short grades.

11. If it’s quite hilly or mountainous use the engine’s full operating range before gearing down.

12. As you crest a steep grade, don’t mash the throttle to get back to cruise speed. Use gravity instead.

13. Plan your routes to maximize time on multi-lane highways.

In the end, the two keys are patience and more patience.