Table of Contents
cars have a weight problem. Consider the Mini, designed to save precious fuel during rationing; it has increased in size. It’s not alone. Cars have been getting bigger and the rise of the SUV has only accelerated the trend.
Electric cars may look the same (for now), but they have one important difference: a heavy battery.
Our EV Mythbusters series has taken a wild ride through the common (but often ill-informed) criticisms of electric cars, from range anxiety to carbon emissions, mining and air pollution. This latest episode asks the question: will electric cars prove too heavy for our roads and infrastructure?
The claim
After years of overloading our roads, the extra strain on the battery has prompted some people to wonder whether the arrival of the electric car will destroy our roads, bridges and car parks.
Matthew Lynn, a columnist at the Daily Telegraph, wrote this month: “It is far from clear whether the charging infrastructure will be in place, or whether roads and bridges will be able to cope with the heavier vehicles.”
Greg Knight, a Conservative MP, asked the British government last year to test “the suitability of the strength of car parks and bridges to safely support the extra weight of electric vehicles”.
The Asphalt Industry Alliance has claimed that smaller roads could be vulnerable to increased pothole formation, and the Daily Mail wrote: “Multi-storey car parks could be at risk of collapse.”
The science
Electric cars can be very heavy. Automagazine said General Motors’ massive Hummer “looks even heavier than it is” – an impressive feat considering it weighs more than four tonnes. A third of this is the battery pack that can power one of the largest cars over a range of more than 500 kilometers. It is large.
A more reasonable electric car would be the Tesla Model Y, weighing two tons. By comparison, Jaguar Land Rover’s Range Rover weighs 2.5 tonnes before people get in, while newer versions of Ford’s F-150 pick-up – the US bestseller – can weigh as much as 2.7 tonnes, depending on the model.
Yet campaign group Transport & Environment calculates that EVs are on average between 300 kg and 400 kg heavier. For every 150 km of range, this adds about 100 kg of battery weight, says Lucien Mathieu, automotive director of the Brussels group.
Heavier vehicles mean there is more friction between the tires and the road surface, and more stress is placed on what is underneath the car. This means that roads deteriorate more quickly. Academics at the University of Edinburgh in 2022 calculated that between 20% and 40% extra wear and tear on the road surface – think potholes, the driver’s bane – could occur with battery vehicles compared to combustion engines.
However, the analysis (which did not carry out real-world testing) found that any additional wear and tear is “overwhelmingly caused by large vehicles – buses, heavy trucks”. The wear and tear on cars and motorcycles is “so low that this is not of concern,” they said.
On to bridges. Colin Walker, head of transport at the think tank Energy and Climate Intelligence Unit, said there are very few roads or bridges in Britain with a weight limit of less than 7.5 tonnes. (Anything over 3.5 tonnes requires a HGV permit in the UK, at least for younger drivers.)
Engineers talk about ‘safety factors’ when designing structures. Take the maximum design load and then build the structure so that it can withstand much more stress, so that there is some breathing room. Steelwork in bridges is generally constructed with a safety factor of between five and seven times the expected load, giving them ample room for an additional 300 kilos.
National Highways, which manages Britain’s motorways and A-roads, is not concerned. A spokesperson said: “Our bridges are designed to support heavy 44 tonne trucks, so we are not concerned about the increased weight of much lighter EV cars.”
after newsletter promotion
Any comments?
Clearly there are limits. The increase in size could theoretically cause problems for some of the oldest car parks, said Kelvin Reynolds, chief technical officer of the British Parking Association.
He said car parks built in the last decade would not pose any problems because they were built with heavy-duty SUVs in mind, but “older car parks may pose some initial risks that need to be addressed – not that that cannot be addressed , but that needs to be addressed.”
There are options for owners of parking garages. They could undertake works to strengthen their buildings – although this could be difficult and expensive. Or they could limit the number of cars allowed on each floor. That could lead to a loss of profit, even though the losses would likely be minimal for many parking garages.
“The transition is going to be the challenge,” Reynolds said. He recommended regular surveys by car park owners to ensure their premises were in good order.
In the longer term, however, the assumption that electric cars will always be heavier is also open to question. Auke Hoekstra, energy transition researcher at Eindhoven University of Technology, estimates that batteries pack twice as much energy into the same weight every decade. If this continues, the weight problem will disappear before it even starts.
T&E’s Mathieu said governments should encourage smaller cars through policies such as taxes and parking fees. This would have benefits far beyond road wear: it would use fewer resources, reduce CO2 emissions and reduce the risk of damage to parking lots.
“It is not inevitable that electric cars will be much heavier” than cars with a combustion engine, Mathieu said. “We can and must move from combustion engines to electric cars, while at the same time reversing the SUV trend.”
The verdict
Extra weight of electric cars could cause problems in the margin and in the short term. However, it is unlikely that most EV drivers will ever experience immediate problems.
Some parking lot owners could be affected, and if electric trucks become heavier when they become widespread, it could mean higher road maintenance costs.
But almost all direct costs will be borne by infrastructure maintenance budgets. The ECIU’s Walker said concerns about extra weight for electric vehicles were simply “vastly exaggerated”. However, he added that automakers do have a responsibility to produce smaller electric cars, after years of focusing on the most profitable SUVs.
The extra weight of electric cars is unlikely to accelerate the destruction of roads, bridges and parking garages. Concerns about weight threaten to distract from the ultimate prize: reducing carbon emissions to net zero.