I was in a mad rush to get to Steamboat Springs, and it was getting dark when I left Salt Lake City. The long stretch of two-lane highway to Colorado was deserted, and though I’m loath to admit it, I took risks. My average speed was 90 miles an hour.

Then I noticed something was wrong with my gas gauge. The “empty” light was glowing, though I’d only gone about 250 miles since filling up. I should have had more than 125 miles worth of gas left in the tank, so I wasn’t worried. The next town was only 60 miles away; I’d get gas there and check the gauge out.

But 30 miles later, my car mysteriously sputtered to a stop. Hours later, a late-night trucker saw my frantically waving arms and pulled over. When I told him something was wrong with my car, he grinned and said, “You’re out of gas.” Despite my insisting that was impossible, he generously poured two gallons into my tank, and the car started right up. “Take it easy on the gas pedal,” he advised as he left.

After that, I learned three things: 1. It really is true that fast driving dramatically lowers your gas mileage; 2. With the right technique, you can easily coax four or more gallons worth of extra mileage out of a full tank; 3. Momentum is your friend.

That’s important information during this season, when many of us pack on miles driving to resorts. If you’re round-tripping between the Salt Lake Valley and Park City, take it easy on uphill roads. Just 5 MPH slower than the speed limit will save money, and delay you by only two minutes. On the downhills, Parley’s Summit is your marker. Take your foot off the gas pedal and coast. Going east, you can coast all the way to the Jeremy Ranch exit. Going to west, you can coast eight miles or more on the way down.

The same is true when coming down the Big or Little Cottonwood canyons. Except on icy days, when you must work at maintaining traction, you can coast all the way from the resorts to the mouth of the canyons.

Gradually, you’ll be able to spot even the most subtle road slopes, and take advantage of them by lifting your foot off the gas pedal. Never step on the pedal when it’s not necessary. For example, if there’s a red light ahead, why waste gas getting to it? Coast on momentum instead.

In highway driving, remember which intersections have lights that last two minutes or more. If you’re making a left turn and that light turns red while the through-traffic light is still green, you may be waiting three or more minutes to get the green arrow again. Turn off your engine. A mechanic told me that it takes less gas to start a car than to keep it idling for two minutes.

Every time you brake, you’re losing money—or rather, losing the gas that’s been used to accelerate your car. Over the course of a tank, this can add up to many miles. Learn to drive with the guiding mantra that having to step hard on the brake pedal is a defeat. If you’re rolling to a red light (while, of course, not impeding any traffic behind you), you’ll quickly lose speed and need only light brake pressure to stop your car. In many cases, the light will turn green—and if you’re still rolling, you’ll need only a mere tap on the gas pedal to accelerate, rather than having to gun it with a gas-guzzling stomp to move from a dead stop.

A warning: This type of driving requires constant vigilance; you must always stay aware of road conditions and how traffic is moving around you. If vehicles are passing you left and right, put on some speed to keep up with the flow. But as time passes, you’ll get accustomed to driving with a gas-sipping technique, rather than the hell-bent-for-leather guzzling mode. A compact model may get more than 100 extra miles out of a full tank. A mid-size model can get at least 75 extra miles. Even the SUV or pickup guzzlers can tack a few miles onto their miles per gallon average. Driving so that you save $8 to $12 on every fill up—over time, it’s priceless.