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All Contents © 2020The Kiplinger Washington Editors
By David Muhlbaum, Senior Online Editor
| December 19, 2019
The price of gasoline today isn’t exceptional — well off the $3+ spikes seen in the early part of this decade. On the other hand, a gallon of regular gas is still significantly higher (when accounting for inflation) than where it was in the 1990s.
Don’t let a “well, it’s been worse” mentality blind you to the fact that filling the tank is taking money out of your wallet, money that could be spent on more fun stuff, or even invested.
When fuel prices spike, lots of tips and tricks to save on gas get trotted out. They’re not all worthy.
We’ve narrowed them down to seven that don’t violate the laws of physics, compromise safety, or insult your intelligence.
Car engineers spend a lot of time engineering pounds, ounces and grams out of today’s cars. Don’t undo their efforts (and the gas savings they represent) by leaving anything unnecessary in the luggage compartment. Golf clubs are a common violator, but so is random dead weight like those items slated to go to the second-hand store one of these days. Or, dear lord, a case of individual water bottles for after-workout hydration.
Every time you accelerate, you’re using gas to get that stuff up to speed with you. How much more? This depends on your car, but the EPA estimates a 1% reduction per 100 pounds. On a per-gallon cost basis, that’s about $0.03, using the EPA baseline figures. Get your stuff in order and you’ll save money, too.
Skweeker via Flickr
When they’re not worrying about the weight of their designs, auto engineers fuss over aerodynamics.
Improvements to how your car cuts through the air bear fruit most at high speeds — highway miles. The most common way drivers hurt their aerodynamics, and thus mileage, is by putting items on the roof.
Do you have activities (cycling, skiing, going down to the beach house) that mandate a lot of equipment? Consider whether you could use a hitch-mounted rack or box instead. Tucked in the slipstream of your car, these have a much smaller mileage penalty.
If you must put items on the rooftop (you’re a paddler, say), remove the rack when you can.
And, finally, if your vehicle came with a factory roof rack that you never use, see if you can remove the crossbars. You’ll save a few pounds this way, too.
Being told to group your errands sounds a bit like a nag, much like the admonition not to use the trunk as a storage locker. “If life weren’t so crazy, I’d be doing that already!” is a common rejoinder I’ve heard.
So, yeh, we know: Stuff happens. Still, we will repeat the reasons why planning ahead can save gas:
Americans continue to wildly overestimate how much fuel it takes to start an engine versus to keep it running. The reality is, once you’re stopped, your car is wasting fuel after about 7-10 seconds of idling. That’s why newer gas cars (and virtually all hybrids) have a feature that shuts the engine off during stops when the brake is applied. The car’s still on, but the engine isn’t. Push the accelerator pedal and the engine snaps back on — off you go.
Some people find this maddening (and in truth the smoothness of the systems varies among vehicles), but the gas savings is real. Watch this video from Engineering Explained to see the science behind these claims.
If you want to maximize mileage, don’t disable the auto on-off feature. And everyone can stop leaving their car on while running back into the house, or whatever short errand you’re doing. You're not an Ice Road Trucker.
No list of gas-saving tips would be complete without the admonition to slow down. There’s no getting around the fact that lower speeds require less fuel, most because aerodynamic resistance increases with the square of speed.
That’s the lecture. But driving to save fuel doesn’t have to be a dull crawl in the slow lane. Try thinking of it this way: brakes turn your money into heat, so can you avoid using them?
This isn’t meant to encourage dangerous behavior like not stopping for stop signs or the like. Rather, anticipate, anticipate, anticipate. Look down the road farther, and coast down when you know that traffic signal’s going to change to red. While hybrid and electric vehicles are best equipped to take advantage of this style (through regenerative braking), many conventional gas cars now engage power-sapping accessories like the alternator during coast-down to maximize fuel efficiency.
As for accelerating, if you know you’re going to be holding a higher speed for a while, like when you’re merging onto a highway, go ahead and shove the gas as hard as you need. Not only is slow acceleration in this situation potentially dangerous, it doesn’t actually save fuel.
All cars built since 2007 have what’s called Tire Pressure Monitoring Systems (TPMS). These do what the name says: monitor that your tires have air pressure.
The hitch is this: That light may not come on until a tire is more than 25% lower than the recommended pressure. And if you wait for that, you’re potentially endangering yourself (an underinflated tire can compromise your car’s handling or even lead to a tire blowout) and wasting money (underinflated tires reduce your gas mileage by roughly 0.2% per pound that they’re low). Doesn’t sound like much, but try this math: If your recommended inflation pressure is 40 psi, and you’re 25% low on air, that’s a 2% hit to your gas mileage. Plus, underinflated tires wear more quickly and unevenly, reducing your tire life.
There’s just no substitute for buying a decent-quality tire gauge (between $5 and $15) and using it at least once a month. Even if you can figure out how to get your TPMS to show each tire’s actual pressure on your dashboard screen, we’d still backstop with a handheld gauge.
Finding the cheapest fuel was once sport for me. But phone apps like Gas Buddy, Gas Guru and Fuelzee make it almost too easy to find the best gas deals. Since you can use them to screen for brands, you can also make sure you’re getting good quality fuel, which, in the long run, matters to the health of your car.
Joining a membership club like Costco or Sam’s Club could also pay off. Figuring how quickly you’ll recoup your membership cost with the per-gallon savings on their discounted fuel is pretty easy math.