The contours of a 30-year-old TV commercial linger in my head. The spot, whose production value matched that of local access programming, aired on the Armed Forces Network in the 1990s when the Air Force had stationed my father overseas. In the lo-fi video, two identical military green vehicles are given the same amount of fuel and the same course to drive. The truck traveling 10 miles per hour faster takes the lead, then sputters to a stop when it runs out of gas. The slower one eventually zips by, a mechanical tortoise triumphant over the hare. The message was clear: slow down and save energy.
That a car uses a lot more energy to go fast is nothing new. Anyone who remembers the 55 miles per hour national speed limit of the 1970s and 80s put in place to counter oil shortages knows this logic all too well. But in the time of electric vehicles, when driving too fast slashes a car’s range and burns through increasingly expensive electricity, the speed penalty is front and center again. And maybe that’s not a bad thing.
You certainly can notice the cost of lead-footedness in a gasoline-powered car. It’s simpler today, when lots of vehicles have digital displays that show the miles per gallon you’re getting, than in the old days when you had to do the math yourself. An EV puts the hard efficiency math right in front of you. Battery life is often displayed in terms of estimated miles of range remaining, and those miles evaporate before your eyes if you climb a mountain or accelerate like a drag racer.
This is no academic concern, like trying to boost one’s fuel efficiency through hypermiling techniques such as gentle acceleration, downhill coasting, and killing the AC. In six years of owning a Tesla Model 3, I’ve pushed its range limits trying to reach far-flung national parks and other destinations where fast chargers are scarce. I’ve found myself in numerous situations where I’ve set the cruise control at exactly the speed limit or slightly below to make sure the car would reach the one and only charging depot in the vicinity. For particularly close calls, I’ve puttered white-knuckled with one eye on Tesla’s in-car energy app — and felt my stomach drop when I found myself underperforming its expectations.
Fortunately, slow works. Three years ago I managed a comfortable round-trip from what was then the closest Tesla Supercharger to Crater Lake National Park by driving there down a 55-mile-per-hour two-lane highway; at freeway speed, my little battery probably wouldn’t have made it. Today, my fully charged Model 3 might make it something like 130 to 140 miles at interstate speed, depending on elevation. Go a little slower and it comes close to matching the 200 miles of supposed range.
Fear is the speed-killer, sure. The chance of being stranded with a dead battery is enough for any driver to be scared straight into observing the posted limit. But having all that data at the ready had already started to affect my driving habits even when there was no danger of stranding myself. It’s hard to watch the range drop when you slam the accelerator without thinking of the Interstellar meme about how much this little maneuver is going to cost us. With the price of electricity at the fast charger rising, I’m much more conscious of wasting a few kilowatt-hours by being in a hurry.
The difference is stunningly clear in the kind of controlled range tests that car sites and EV influencers have been conducting. For example, the State of Charge YouTube channel recently drove the Cadillac Escalade IQ, the fully electric version of the status SUV that is officially rated at 465 miles of range. Driven at exactly 70 miles per hour until it ran out of juice, the big EV exceeded that estimate by traveling 481 miles. With the speedometer held at 60 miles per hour, however, the vehicle went 607 miles — more than 100 miles more.
Granted, the Caddy’s comically large 205 kilowatt-hour battery — more than three times as big as the one in my little Tesla — does the lion’s share of the work in allowing it to go so very many miles. A peek into State of Charge’s data, though, makes it clear what 10 miles per hour can do. Dropping from 70 miles per hour to 60 caused the car’s miles per kilowatt-hour figure to rise from 2.1 to 2.6 or 2.7.
That’s not to say EV ownership turns every driver into an energy-obsessed hypermiler. One blessing of the huge batteries that go into Cadillac EVs and Rivians is freeing their drivers from some of the mental burden of range calculations. With driving ranges reaching well above 300 miles, you’re going to make it to the next plug even if you drive like a maniac.
Even so, the increased awareness of the cost of electricity might make some of us reconsider the casual speeding we all do just to take a few minutes off the trip. That’s a good thing for public safety: Big EV batteries make these vehicles heavier than other cars, on average, and thus potentially more dangerous in auto accidents. And slowing down will be especially relevant as electricity prices outpace inflation. Consumer electricity prices are up nearly 5% over last year and are poised to get worse: The budget reconciliation bill signed by President Trump last week won’t help, as one projection sees it leading to an increase in annual energy bills of up to $290 by 2035.
To be honest, the biggest problem of slowing down a little isn’t really the extra time it takes to get someplace. It’s trying to conserve in a world where 5 to 10 miles per hour over the speed limit is the expectation. I once had to cross 140 miles of wind-swept New Mexico expanse from Albuquerque to Gallup on a single charge, a task that required driving 55 miles per hour in a 65 zone of the interstate, holding on tight as semi trucks flew past me in revved aggravation. We made it. But if you really want to make your electrons go farther, then be prepared to become the target of road rage by the hasty and the aggrieved.
