What Really Saves Gas? And How Much?

Driving Tips

We Test the Tips
What Really Saves Gas? And How Much?
By Philip Reed and Mike Hudson
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Date Posted 11-22-2005
With gas prices so high, the media is awash with lists of gas-saving tips. Well how's this for a tip? If you listen to us, you can see hybrid-type savings without having to buy a new car.

By changing your driving habits you can improve fuel economy up to 37 percent right away (depending on how you drive). Combine several tips and perform routine maintenance and you will save real dollars, not just pennies.

A miracle? All we did was take several of the most common tips out there and put them to the test over a remote 55-mile route in the high desert of California. Some of them worked like a charm. Some of them didn't work at all. We'll give you the breakdown.

These tests were done under real-world conditions — not in a government lab somewhere. Our results can be matched by anyone — even you.

The wonderful part about what we found is that improving your car's mileage is just a matter of changing your habits. Stack a few of these winners together and we'll bet that you'll see a substantial savings at the pump — without the need for a new car.


Test #1 Aggressive Driving vs. Moderate Driving

Result: Major savings potential

The Cold Hard Facts: Up to 37 percent savings, average savings of 31 percent

Recommendation: Stop driving like a maniac.

Aggressive vs. Moderate Driving: read the entire test


Test #2 Lower Speeds Saves Gas

Result: Substantial savings on a long trip

Cold Hard Facts: Up to 14 percent savings, average savings of 12 percent

Recommendation: Drive the speed limit.

Lower Speeds Saves Gas: Read the entire test


Test #3 Use Cruise Control

Result: Surprisingly effective way to save gas

Cold Hard Facts: Up to 14-percent savings, average savings of 7 percent

Recommendation: If you've got it, use it.

Cruise Control: Read the entire test


Test #4 A/C On, Windows Up vs. A/C Off, Windows Down

Result: Nice in theory; not true in practice

Cold Hard Facts: No measurable difference (unless you open the sunroof, too!)

Recommendation: Please, make yourself comfortable.

Air Conditioner: Read the entire test


Test #5 Check Your Tire Pressure

Result: Important for safety and to reduce tire wear

Cold Hard Facts: No measurable effect on the vehicles we tested

Recommendation: Check your tire pressure often but don't expect a big savings.

Tire pressure: Read the entire test


Test #6 Avoid Excessive Idling

Result: More important than we assumed

Cold Hard Facts: Idling saves an average of 19 percent

Recommendation: Stopping longer than a minute? Shut 'er down.

Excessive idling: Read the entire test


The Tests

Our results are based on two separate fuel testing sessions. On each occasion we took two cars from the Edmunds.com long-term fleet and drove on a 56-mile test loop. Our route circled Owens Lake near Lone Pine, California, at the foot of Mount Whitney, the tallest mountain in the lower 48 states. We chose the route because it was so deserted we could vary our speed and driving style without interfering with the flow of traffic. The only other cars we saw on the route were a caravan of test vehicles from Mercedes-Benz. We drove the loops back-to-back to ensure that we were comparing similar wind and temperatures. We logged our results and later put them on a spreadsheet where the results were averaged.


Test #1: Aggressive vs. Moderate Driving

This is gonna hurt. Our tests showed that the most significant way to save gas is: you. And we're talking massive fuel economy gains. Think you need a hybrid? Chances are you've got hybrid-style mileage in your gas pedal foot. Don't mash the gas when you start up. Take the long view of the road and brake easy. This tip alone can save you unbelievable amounts of gas. If you slowed your 0-to-60-mph acceleration time down from your current 10 seconds to a more normal city pace of 15 seconds, you'll feel the savings immediately.

Method: We conducted this test four times. The first time we did the full 55-mile loop once by accelerating aggressively 15 times at 3/4-throttle from zero to a cruising speed of 75 mph. We also applied the brakes hard to come to a full stop. Then, we drove the second loop by accelerating moderately 15 times at 1/4-throttle to a cruising speed of 70 mph. We braked lightly to a full stop. In the second set of tests we drove 25 miles making 25 rapid accelerations to 65 mph at 3/4-throttle. After 1 minute of cruising we braked hard and repeated the cycle up to 65 mph. We then drove the same distance making 25 moderation accelerations to 60 mph at 1/4-throttle. After 1 minute of cruising we applied the brakes easily and came to a full stop.