Potentially illegal, possibly dangerous, but definitely efficient

The fuel-saving secrets of hypermiling

We’re obsessed with cars. This is true here in the U.S., of course, but we’re part of a global phenomenon, not a gas-addled outlier. Germany has its high-speed autobahn, a beautiful asphalt monument to speed. The Japanese auto industry turned compact cars from cheap metal into an artform. Spend any time in Kenya, and you’ll likely catch a ride in one of the lavishly decorated matatus, which are as much a cultural institution as a decentralized public transit network. 

I could keep rattling off examples of global vehicle love, but this adoration isn’t controversial. The world cranks out 80 million automobiles per year. Enterprising internetters have surmised that humanity has produced more than 2 billion cars and trucks since Carl Benz started the craze 136 years ago. And in the U.S., we average nearly two vehicles per household, even though 8.9 percent of families—nearly 3 million of us—don’t have one at all. 

Environmentally speaking, this adds up to a five-alarm shitfire. Transportation creates 37 percent of global emissions, and personal transportation is responsible for 41 percent of that chunk. Math math mathitty math… Our own cars (and trucks and motorcycles) contribute 15 percent of global emissions, around 6 gigatons of greenhouse gasses every year. 

OK, we all feel bad now. Sorry to bring you down. Now let me lift you up! Whether you drive a sparkling-new EV or a decades-old diesel beater, it’s pretty easy to reduce the amount of energy it uses, and, by extension, the emissions it creates. More than easy, it’s fun. Once you start playing the mo-mileage game, it’s hard to stop.

Disclaimer: some of what you’re about to read is illegal and/or stupid and/or dangerous. Don’t do bad stuff! And definitely don’t use my name if you get caught. Unless the cop is impressed, in which case, please share this newsletter with them (and everyone else you know). 

You might have heard the term hypermiling before, but just in case you don’t know the jargon: Hypermiling is the pursuit of getting more miles per unit of energy than a vehicle ordinarily delivers. Hypermilers compete with one another to see who can extract the most distance out of a full tank or battery, often going to extreme lengths to break records. A regular person shouldn’t try to match those pros, but some of their less intense techniques can help anyone net up to a 20-percent increase in their car’s efficiency. I’m sorry, I have to say it: Your mileage may vary.

This level of savings could have a staggering impact. In the U.S., our vehicles burn 135 billion gallons of gasoline per year. 20 percent of that is 27 billion gallons, which produces around 240 million metric tons of planet-warming CO2. Of course, we can’t expect the entire country to start hypermiling and cut our fuel bill by 20 percent. But you could cut yours a little: Even if you only drove 10-percent more efficiently in an average, 36 mile-per-gallon vehicle, you’d pump more than 40 fewer gallons of gas in a year.

I absolutely cheated to get this photo.

I know this because I called one of the best hypermilers in the world. Kevin Booker is part of the three-person team that nabbed the Guinness world record for lowest energy consumption while driving from one tip of Great Britain to the other. The trio drove a Ford Mustang Mach-E at an efficiency of 6.5 miles per kilowatt. (The Mach-E is an EV.) In more familiar terms: They started with a full battery, charged once for 43 minutes, and managed to travel 840 miles. 

A Mach-e specced for range is good for 312 miles on a full charge, so even if they managed to juice all the way up during that 43-minute stop (they didn’t), that would still be an astonishing 34 percent more than that car should do: 420 miles on a charge. 

How did they manage this? “It’s not just one big thing, but more of a series of little actions,” says Booker, which is great news for us. Because even if we can’t be extreme hypermilers, we can integrate certain techniques into our daily drives. Here are some of Booker’s top tricks.

Junk out of the trunk

“Weight is the big thing,” says Booker. We have all been guilty of using our trunks as storage lockers, but it might be time to evict those old blankets and jugs of water. If you have a roadside assistance plan and don’t find yourself in remote areas much, you could even ditch your spare tire. An extra 100 pounds of gear in your rear can reduce fuel economy by 1% or more. 

This may not seem like a big deal, but “it’s all about incremental gains,” says Booker. In our hypothetical average Americamobile, 1% of annual fuel consumption is around 4 gallons of gas. And all you had to do was clean out your car. 

Go gentle into that good lane

“Every set of traffic lights isn’t a drag race,” says Booker. “You’ve got to get gently up to speed.” It takes a lot of energy to overcome the coefficients of friction that keep your tires from rolling freely, and it takes even more to get them rolling quickly. If you want to beat those forces more rapidly, you have to introduce more energy into the equation. In your car’s case, energy = fuel. 

Some sources say that accelerating gently can cut your energy consumption by 40 percent. Then, once you’re up to speed, and moving through traffic, you can consider how else to dodge friction.

I’m not saying you should run red lights, but…

Every time you bring your car to a stop at an intersection, you have to overcome those forces of friction to get your car moving again. “The idea is to keep the momentum,” says Booker. Again, that doesn’t mean you should run a stop sign or blow through a red light to save gas, but it does mean you should try not to stop. What’s the difference? 

“If you see that the light is red down the road, you know it’s going to turn green again,” says Booker. “So try to arrive after it’s turned.” Similarly, “if the light is green, it’s going to turn red.” Try to time your arrival at the intersection so you don’t have to stop. “It’s just about reading the road ahead,” he says. Booker also tries to keep his car in the appropriate gear for the speed he’s going. “Hypermiling in a fueled car is much easier with a manual transmission,” says Booker. One more reason to #savethemanuals.

Mind your tires

As the only part of your vehicle that touches the ground, your tires are arguably the most important part of your car. They make a huge difference in how well you can stop and turn and negotiate challenging conditions. They’re also a crucial factor in your car’s fuel economy. If you’re shopping for new tires, make sure you buy ones that are marked as low rolling resistance. This means that their rubber is formulated so that it takes less energy to move. 

But you don’t have to just buy your way into tire performance. “Tire pressures are so important,” says Booker. “So many people don’t check them.” Sure, it may be a pain in the ass to navigate the quarter-hungry machine at the gas station, but this is a crucial part of saving fuel. A drop in pressure of a single psi can increase your rolling resistance by 1.4 percent. That adds up as your tires air down. Booker recommends looking at the plate on your door jam or in your owner’s manual and inflating your tires to the top end of the range listed there. 

Some people will tell you to over-inflate the tires, but “for safety reasons, I wouldn’t do that,” says Booker. I, on the other hand, do, and it definitely helps my mileage. This is probably stupid and you shouldn’t do it, but I’ve talked to enough industry folks to be convinced that one of the considerations engineers make when recommending tire pressures is ride quality. I don’t mind a firmer ride if it gets me better fuel economy. My car’s recommended tire pressure is 32 -35 psi. I pump them up to 40.

Another thing to remember about tire pressure is that it changes with the outside temperature: They go down when it gets cold, so it’s important to pump your tires up when the days get chilly.

Got it on the first try this time: “driving a car on a gas can,” from the Dall-E image generator.

Climate Control

The knock on air conditioning has always been that it lowers your gas mileage because your engine has to turn a hefty compressor to make that cold air; in older cars, this is certainly true. But “over the years, these systems have gotten more modern,” says Booker. “In some cases it’s more efficient to run your air conditioning than driving with the windows down.” 

One example is on the highway. “If you have your windows down at high speed, it creates a lot of drag,” which can sap your mileage, says Booker. In that case, it’s more efficient to run your A/C—unless you only open your window a teensy bit. “If you have it open just a crack, that’s more efficient than using your air conditioning,” he says.

It’s different in EVs. “The heating is worse than the air conditioning in an electric car,” says Booker. “A fueled vehicle naturally wastes energy as heat, which is what you use to wearm the cabin. But with an electric car, it has to make that heat.” That means powering up a resistive heater (basically a space heater) for the entire duration of your trip. Some newer EVs use heat pumps, which are much more efficient, but it’s still a large power draw. In one EV that Booker tested, it took 7 kilowatts of power just to warm up in the winter time. That’s more than 10 percent of that vehicle’s battery capacity.

Know your brakes

Another EV-specific trick is to get crafty with how you stop. In a gas- or diesel-powered car, when you hit the brakes, grippy pads clamp down on a rotors that are attached to the axles that drive your wheels. (I’m not getting into drum brakes, but a similar principle applies.) An EV, however, doesn’t just use a conventional braking system. 

You might have heard about regenerative braking, often abbreviated as “regen.” This is an EV- and hybrid-specific system that allows the same electric motor that drives the wheels to act as a brake by reversing the direction it wants to spin. Instead of spending energy to go, the same magnetic principles allow it to harvest electricity by slowing the wheels down. Booker recommends figuring out how to use regenerative braking as much as possible. 

“When you press the brake pedal, there’s a point where you’re using the motor to slow you down, and there’s a point where the friction brakes engage,” he says. “The key is knowing that point.” This is all about feel, and you’ve just got to pay attention to what the brakes feel like when you’re hitting them. Then, as you drive, you can try to do all your braking with the motor rather than the pads, sending extra volts into your battery pack. If your car has a setting for regenerative braking, max it out.

What’s this button do?

Your car has other settings that can help you cut fuel consumption as well. “I know it sounds basic, but if your car has a button that says ‘eco,’ press it,” says Booker. A setting like this will tell your transmission to shift less aggressively, and in some cases even reduce the amount of fuel the injectors squirt into your engine. 

Cruise control is also your friend. “The computer is much better at keeping a constant speed than an average person,” says Booker, and that’s crucial. Even small variations in speed on the highway—drifting up and down by a couple miles per hour as you search for the next podcast—can really sap your mileage. 

Of course, the most efficient way to reduce your fuel use is to not drive. Take public transit. Walk. Ride a bike. Or stay home. Hopefully, some day soon, these options will be available to everyone, no matter where they live. Until then, I’ll be playing the mo-mileage game, trying to squeeze every last inch out of any fuel that I use. 

Take care of yourself—and the rest of us, too