Electric vehicles weigh more than their internal combustion engine counterparts, and that has implications for maintenance, safety and even pollution.
The additional weight of EVs is a challenge for automakers today looking to increase at least half of their sales to be all-electric by the end of the decade. They see the prices increase on raw materials and fear a shortage of them in the future. EV batteries require structures that can hold the additional pounds. But the heavier vehicles also have implications for owners and, some say, society, too.
Take Ford Motor Co.’s F-150 Lightning pickup, which starts at 6,015 pounds. That’s 22% more than the 4,950-pound curb weight, which includes a full tank of gas, of the equivalent traditional F-150. Meanwhile, the starting weight of an electric Hyundai Kona is 28% heavier than the gas-powered model, and the Nissan Leaf is 35% heavier than the starting weight of its gas-powered equivalent, the Versa.
Auto leaders like Jeep maker Stellantis NV CEO Carlos Tavares have warned about the potential for raw material shortage risks as EVs proliferate: "Carmakers are going to increase EV progress," he said in May, "which will increase the weight of the cars, which will then increase the problem on the raw material supply shortage risk."
That's a challenge for automakers. For customers, other drivers and other users of the road, here is what to know:
Accelerated tire wear
Without transmissions or the need for oil changes, EVs have fewer maintenance needs than ICEs. Some EV owners, however, do report having to replace the tires on their vehicles sooner than on a gas-powered vehicle.
Steven Misrack of San Diego is on his second Chevrolet Bolt, opting to replace his 2017 model for a 2020 for the improved range. He previously replaced the four tires on his '17 Bolt for around $700 after 30,000 miles. On his previous Toyota Tacoma truck, he'd gotten past 50,000 miles.
"The (Bolt) tires have low rolling resistance, so they wear out faster, but I'm getting better range because of it," Misrack said. "They were the same price for off-road tires on the truck. It was a little bit surprising."
He's doing less highway driving, but more city driving in the '20 Bolt and suspects he'll have to replace the tires on it before the end of the year, when he expects to hit around 20,000 miles.
“I generally don’t tear up the road on the street,” Misrack said. “That’s more dangerous with pedestrians around. I’ll tell you, many times if there are no vehicles around on the freeway, I’ll floor it, and I’m gone. It’s that torque and acceleration. The car just goes.”
Because EVs are heavier, they've created a new high-load capacity tire market with manufacturers specifically targeting EVs, said Jen Stockburger, Consumer Reports' director of operations who oversees its tire program. They may have more sidewall layers and typically have less rolling resistance, which seeks to benefit range. That, however, can come at the expense of grip in wet conditions.
"It's gotten better," Stockburger said. "They're becoming less and less of a compromise, not always, but sometimes."
She adds that in addition to weight, the instant torque of EVs scrubs more quickly, which can wear down tires faster. That's especially the case for more aggressive drivers.
Nick Anastasiadis, 47, of Jackson, Michigan, replaced the from-the-factory tires on his 2020 Nissan Leaf a few weeks ago after surpassing 41,000 miles. It's his second Leaf after his employer installed free charging stations at work, and Anastasiadis says he's never had a vehicle that requires less maintenance and service.
"Is there more wear?" he said. "There may be more wear, but it’s probably minuscule."
More road repairs?
In general, studies show heavier vehicles do more damage to roads than lighter-weight vehicles, but experts say that areas with crumbling roads will not appreciably be further damaged by EVs.
Greater damage comes from commercial semi trucks that weigh tens of thousands of pounds. Given the comparatively small difference in heft between EVs and ICEs, it's not expected that more EVs will require more road maintenance and repairs.
"The difference between the weight of a standard light vehicle with an internal combustion engine and an EV is not significant enough to cause concern," Michigan Transportation Department spokesman Jeff Cranson said in an email.
That's good, given state gas tax revenues are expected to decline by $2 billion by 2050, according to a report from two free-market think tanks, the Michigan-based Mackinac Center and the Los Angeles-based Reason Foundation. The report recommends replacing that lost revenue by charging drivers by the mile. Currently, to register an EV in Michigan, drivers have to pay an additional $140 fee.
Without a new system, "You'll have a significant share of vehicles on the road paying almost nothing," said Chris Douglas, an associate economics professor at the University of Michigan-Flint, one of the report's authors. "By 2050, half of vehicles on the roads will be EVs. If you have that burden falling on the other half, that doesn't seem feasible."
The report didn't examine EVs weighing more, Douglas said: "If it weighs 500 pounds or more, it isn't going to make a lot of difference."
California, the state with the highest EV adoption rate, doesn't factor EVs into its rate of roadway wear because they weigh under 10,000 pounds and aren't expected to create additional maintenance costs, according to Nicole Mowers, a spokeswoman for Caltrans, the state's transportation agency. California has a road improvement fee for zero-emission vehicles of $102 that is adjusted annually for inflation as well as a transportation improvement fee assessed based on a vehicle's value ranging from $28 to $196. Caltrans is assessing an alternative to a gas tax that is levied based on how much drivers use the road, as well.
Norway, the country most quickly adopting EVs, also says it hasn't collected data indicating the need for additional maintenance on roads as EVs have proliferated, said Johan Vasara, the Transportation Ministry's state secretary.
"Now, that said, today we have still less than 20% of our cars in Norway which are electric," he said. "So, it's maybe still early to say anything clearly about that."
For decades, vehicles have gotten heavier from electronics, technology and safety systems and consumers preferring larger SUVs and trucks, said Sigve Jarl Aasebø, senior adviser at the vehicle section of the Norwegian Public Roads Administration. What is more damaging for roads than weight, though, is studded tires, aggressive driving and higher engine power.
"The weight of the vehicle and battery pack is a secondary factor," he said. "It's probably fifth or sixth place."
Norway's previous right-of-center government had estimated toll discounts and EV subsidies were creating a more than $2.8 billion (19.2 billion Norwegian kroner) hole in annual revenues. The center-left minority government that took over in October recently decided to extend those breaks, but Vasara says there are pushes to wind that down in the coming years.
"It's a tough debate in Norway on how to proceed from this," he said, "because of course, there's voices who don't want to lift any tolls for electric cars, because of the climate argument, but also in general, because electric cars are now the mainstream cars. Of course, car owners and car drivers aren't necessarily eager to pay more in their everyday life."
Pedestrian risks
The growth in popularity of heavier vehicles in the form of SUVs and trucks has been cited as one of the reasons for increasing pedestrian deaths in recent years. The National Highway Traffic Safety Administration estimates nearly 43,000 people died in motor vehicle traffic crashes last year, the highest number of fatalities since 2005 and at a 10.5% year-over-year increase, the largest annual percentage rise in the reporting system's history. Fatalities among pedestrians and cyclists also have risen faster than those within vehicles.
With EVs growing even heavier, some academics worry these cars and trucks could increase safety risks. In an op-ed last year in the scientific journal Nature, scholars led by Blake Shaffer, an assistant professor at the University of Calgary in Alberta, noted the likelihood of passengers being killed in a collision increase by 12% for every 1,100 or so additional pounds.
"Under the energy systems operating in most countries today, the cost of extra lives lost from a 700-kg (approximately 1,500-pound) increase in the weight of an electrified truck rivals the climate benefits of avoided greenhouse-gas emissions," the authors wrote.
The op-ed suggests in addition to taxing electric vehicles based on mileage, they also could be taxed for additional weight as a disincentive. New York state and France levy additional fees for heavier EVs. The academics note battery technologies that use lighter-weight materials like silicon over graphite, solid-state batteries as an alternative to batteries with liquid electrolytes, and wireless battery monitoring systems could help lighten the load, too.
NHTSA says it's reviewing studies by independent researchers to better understand the potential effect of vehicle size in crashes. It adds manufacturers must certify that their vehicles comply with applicable federal motor vehicle safety standards.
Increased tire dust
EVs don't have tailpipe emissions, but some researchers are suggesting EVs could carry health risks from carcinogenic particles wearing off tires because of their heavier weight.
U.K.-based consulting firm Emissions Analytics estimates wear on all four tires of a vehicle results in emissions of 100 milligrams of particles per mile and that adding the weight of a battery results in a 21% increase in tire emissions, CEO Nick Molden said. U.S. regulations limit maximum tailpipe particle emissions to 3.2 milligrams per mile.
"There's significant cause for concern," Molden said. "In terms of total tire wear emissions, the electric vehicles could make the situation a lot worse."
These aren't carbon emissions, but tire materials often come from crude oil just like gasoline. Instead of the core of these particles being carbon, they're some elastomer or polymer synthetic rubber material. Still, volatile organic compounds surround that core, Molden said, and when those compounds are exposed to the air, they create ozone — smog that can lead to respiratory issues and increase the risk for cancer.
Smaller particles can end up in the air. Larger particles can fall into water and soil. Recent studies suggest one tire chemical, 6PPD, has negative effects on salmon and other sea life off the U.S. West Coast.
"The amount of academic research here is very limited and not conclusive," Molden said. "It does get into the food chain. We just don't know in what concentration and therefore how dangerous it is."
Researchers at the U.K.'s Imperial College London and Royal College of Art known as the Tyre Collective even have created a device that in tests collected 60% of airborne particles.
The research, however, comes with a major footnote: Emissions Analytics hasn't actually collected data from an EV. The figures come from a non-electric car with the added weight of a battery so as to avoid other potential variables.
On the other hand, regenerative braking in actual EVs reduces wear on brakes but also on tires. Molden notes some ICEs do have regenerative breaking, as well, and that the immediate torque from EVs is a countervailing measure. He also adds how a person drives also has a lot to do with tire emissions and that easygoing driving can offset the increase from an EV's weight.
"An eco driver may make things better," he said, "but a person driving a Tesla in Ludicrous Mode is probably going to make it much worse."
