Are cars getting too big for the road?

Are cars getting too big for the road?

BBC — 2024-02-08

Automotive Industry

In some parts of the world, cars have always been on the larger side. But now these behemoths are spreading – and the consequences are still being figured out.

The 2024 Chevrolet Suburban, a nine-passenger sports utility vehicle (SUV), measures 225.7 inches (18ft/5.5m), and is advertised as "a room with a view". A seven-seat, fully electric crossover vehicle designed by Kia houses an 800-Volt battery that weighs, on average, 1,000lb (450kg). An electric Hummer SUV, meanwhile, has a maximum width, including mirrors, of 93.7in (2.4m).

Large cars are becoming ever more popular. In fact, the size of the average car is growing wider at a rate of 1cm (0.4in) every two years, according to the non-profit Transport and Environment. With this increase in size comes some equally large problems, from environmental repercussions to safety hazards, and the sheer difficulty of manoeuvring cars in streets and parking spaces designed for smaller models.

As the city of Paris, France, votes to triple the parking fees for visitors' SUVs in its streets, what can be done to remedy the challenges that come with large cars?

How the car got so big

Car shapes and sizes have steadily ballooned since the late 1970s. The reasons for this increase are various and complex. The addition of safety features like lateral and frontal airbags and "crumple zones" required more space, while consumers began to seek out luxury, exotic and import vehicles. Finally, the auto industry incentivised the purchase of trucks and SUVs over lighter sedans.

In 1975, the US Congress amended fuel economy regulations on new passenger vehicles in the form of Corporate Average Fuel Efficiency standards. These standards determine fuel-economy targets, but instated more lenient requirements for light trucks and SUVs than standard cars. The standards have been updated since, but still allow lower fuel-efficiency standards for larger vehicles.

There are other factors at play too. It used to be the case that a single manufacturer would offer smaller vehicle variants in Europe, South America and parts of Asia, while consumers in the US (and China, the world's largest car market) could select from a range of much larger options.

That variation is disappearing. The majority of vehicles in the UK used to be designed and produced in Britain, with narrow English streets in mind. Now, vehicles in the UK (and the EU) tend to be larger imports designed to navigate the urban sprawl and looping freeways found elsewhere. In 2020, the average mass of new cars in the EU and the UK increased to 1.457 tonnes, 3% higher than in 2019 and 15 % above 2001 levels.

The shift towards heavier (and therefore less fuel-efficient) conventional vehicles increases both oil demand and Carbon Dioxide emissions; consider that global Carbon Dioxide emissions of SUVs are nearing 1 bn tonnes.

"This is a phenomenon that has spread throughout the globe; we see SUVs making inroads in Europe, China and South Africa due to a combination of factors," says Apostolos D. Petropoulos, an energy modeller at the world energy outlook team at the International Energy Agency headquartered in Paris, France.

Big cars come with big challenges

Even a stationary SUV can be a significant problem in a city that evolved around smaller cars. In 2023, Which? – an organisation that tests consumer products and services – found that 161 car models were too big for the average parking space in the UK. Twenty-seven of those models were so wide that it would be difficult to open the doors while constrained within a single parking bay.

In the EU, the average width of new cars has now surpassed 180cm (5.9ft), which is often used as a lower threshold for on-street parking in Europe. Meanwhile in the US, the strain on parking exacerbated by SUVs has been making headlines for more than 20 years.

A problem too, is the rising emissions that come with bigger vehicles. One report, by the US Environmental Protection Agency, notes that "all vehicle types are at record low Carbon Dioxide emissions; however, market shifts away from cars and towards SUVs and pickups have offset some of the fleetwide benefits".

In other words, bigger cars are diminishing our climate emissions gains. And it is worth noting that most car manufacturers offer smaller, more efficient alternatives. Road deaths are seen as an inevitable consequence of mass mobility in many countries, yet in this debate one factor is rarely cited: the increased bulk of cars.

Shifting SUVs to electric isn't a complete solution either. While the switch to electric vehicles is a valuable step toward net zero emissions, there are drawbacks as those vehicles increase in size.

Cars fitted with electric batteries can also become weighty projectiles in the event of a crash; according to the IEA's 2023 EV Outlook, "Battery electric SUVs often have batteries that are two- to three-times larger than small cars."

Electric models of SUVs come with their own climate costs. In 2022, around 55% of the available EV models available worldwide were SUVs, and demand has seen consistent growth. 

The architecture of an electric SUV is a complex system involving batteries, motors, sensors, electronic controls, auxiliary equipment, wiring, housing and other components. The batteries that power the majority of EVs rely on raw materials such as lithium, cobalt and nickel. Mining for these resources has its own environmental impact. Finally, larger vehicles will require suitable charging stations, which in turn puts stress on our electric grids.

When shopping for a gasoline-powered car, consumers often focus on miles per gallon. Plug-in vehicles, by contrast, don't use mpg as a metric; an EV's energy consumption is measured in kilowatt-hours per 100 miles (160km). Bigger cars require more kilowatt-hours: an electric sedan, for example, requires roughly half as many kilowatt hours as does an electric SUV, according to Petropoulos.

That's not to say EVs aren't still a better climate choice than conventional cars. "While EVs' production is more carbon-intensive than that of gas-powered cars, this difference quickly disappears; a car with an internal combustion engine produces emissions over the course of its lifetime, whereas an EV does not," says Laura LoSciuto, leader of the Battery Circular Economy Initiative at the Rocky Mountain Institute in Colorado. "EVs are an overall net win emissions-wise, even if the grid on which it relies is powered by fossil fuels.... [Our] transportation system needs to be electrified, period, despite the issues with car culture," she says.

Rising US road deaths

Electric SUVs are equipped with bigger batteries because these vehicles have higher power needs. But EV (and conventional) SUVs are also geared toward better performance, meaning it's not just the weight and size of these vehicles that affects traffic safety – it's the way they're driven too. "We can attribute some of the dangers of these bigger cars on the behaviour of the consumers," says Petropoulos. "They want to accelerate faster, which requires more battery power."

The New York Times recently highlighted the "exceptionally American" problem of rising road deaths. Roadways are becoming safer in many developed countries across the world, but not the United States.

Some design trends may not be helping. Many newer, behemoth models have high hoods, which pose distinct safety hazards. A US study of nearly 18,000 crashes involving pedestrians found that SUVs and vans with a hood height greater than 40in inches (102cm) were about 45% more likely to cause fatalities than those with a height of 30in (76cm) or less.

Another study of 3,400 vehicle crashes in the US where a pedestrian was struck found a link between the front-end vehicle height and the risk of the pedestrian's death. Raising the front-end of the vehicle by 10cm (4in) was linked to a 22% increase in pedestrian fatality risk, the study found.

"A number of alarm bells are going off, and the responses are staggering in how ineffective they are," says Kevin J. Krizek, professor of environmental design at University of Colorado Boulder, who co-authored a white paper on fatal road crashes, or "traffic violence", that was submitted last month to US Secretary of Transportation Pete Buttigieg.

"In high school physics, force is a function of mass and speed, but in the world of vehicles, there's a third deadly factor: the design of the hood," says LoSciuto. "The higher and more angular the hood, the greater the risk." Frontal blind spots large enough to hide adults and children can lead to fatal accidents. "Unlike their shorter, sloped counterparts, these towering hoods don't just hit – they can shove victims to the ground and under the vehicle," says LoSciuto.

Perhaps there's a future in which we're simply less dependent on big cars. Is there an alternative type of transportation system that pivots away from bigger, faster vehicles altogether?  

"The optimal solution sits before us: retrofitting streets to make them safe for people using myriad smaller and lighter vehicles," says Krizek. "Fleet operators already await movement on this front; economic development incentives could be provided to spur companies to produce more of these types of vehicles (hundreds already exist), which bolsters the idea."

There are signs of some cities moving in this direction already. Even traditionally car-centric European cities such as Brussels are considering restrictions on SUVs, even as Paris puts its heavy parking charge on visitors using them. Other policymakers in New York are proposing to rein in large cars through tax policies like weight-based registration fees.

But for some cities, from London to New York, the answer may be not to single out large cars, but encourage other forms of transport altogether.