Why driving a bigger car increases risk taking – and what to do about it
08/31/2022
5 min
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Based on an interview with Bart Claus on his paper “The Car Cushion Hypothesis: Bigger Cars Lead to More Risk Taking—Evidence from Behavioral Data,” co-written with Professor Luk Warlop, published in Journal of Consumer Policy, February 5, 2022.
Car driving is integral to modern society, but comes at a high cost in terms of public health. How can this cost be mitigated? As cars on the market – and on the roads – become larger, Professor Claus examines the link between car size and risk taking not only at the wheel but also as a general behavior, and suggests ways to tackle this issue and improve safety.
The Impact of Car Driving on Society
Injuries caused by road traffic accidents will cost the global economy US$1.8 trillion between 2015 and 2030, which represents an annual tax estimated at 0.12% of global GDP, according to research published in The Lancet Public Health. The World Health Organization states that approximately 1.35 million people each year die worldwide as a result of road traffic accidents. Those affected are in more than half of cases, the most vulnerable on the roads, such as cyclists and pedestrians.
Car driving is central to this problem. Much is done to try and mitigate the risk of car driving by deploying cars with safety equipment and legislating to make both vehicles and roads safer. However, little consideration has been given to driver risk taking and car size in this equation. Understanding what leads drivers to take risks has the potential to mitigate the cost of car driving to society.
To date, the relationship between car size and risk taking is not well understood. On the one hand, consumers pick big cars because they perceive them as safer, lowering risk. On the other hand, evidence shows that big cars are much more likely to be involved in accidents which suggests drivers of big cars take more risk.
Cars are Getting Bigger
The number of large cars on the roads is increasing. According to the IEA at least 35 million more SUVs were added to the roads worldwide last year with record levels reached in France, the United Kingdom, Germany and China in 2021.
At the same time, popular car models have become bigger in recent decades, and a study by UK specialized credit broker Zuto provides some interesting examples. The Ford Mustang has grown by 63 per cent since 1964, while the Mini is 61 per cent bigger and similarly heavier. As Dr Claus explains, if bigger cars change how people drive then the effect of this trend toward larger cars will have a negative impact on road traffic accidents. This led him and his co-author to investigate a car cushion effect: Do bigger cars affect people through providing the sense of a “cushion” so that they take more risk?
Bigger Car Size Increases Risk Taking
The researchers experimented using a very realistic simulator to test behavior differences between behavior of those in small cars and those in large cars. The simulator was produced by Green Dino for driver training. Participants were told either that they were driving a small car (Toyota Yaris) or a large car (Toyota Avensis wagon) but the simulator was set with identical conditions. Participants were requested to drive naturally during the simulation.
The result showed that participants who believed they were driving a larger car drove in a more intense manner and displayed riskier driving behavior than those driving smaller cars. Claus reports, “The car was basically the same – if you step on the gas or step on the brake, you will get the same response from the car, so it is people’s behavior that changes.” People felt more protected in larger cars so they took more risks.
Higher Generalized Risk Taking
A further experiment showed that there are further implications for higher generalized risk taking. The researchers wondered if people would take greater risks when they left the larger car. The study showed that perceived car safety best predicts generalized risk taking, that is, non-driving risk taking too. This is supported elsewhere in the literature. For example, previous research suggests that drivers of heavy goods vehicles often get into accidents shortly after leaving their vehicle. This is due to safety feelings carried over from being inside of the heavy vehicle, transferring beyond the vehicle and leading to excessive risk taking.
Practical Applications
Claus believes governments can consider taxing vehicles based on their size and weight. Not only do bigger cars lead to greater risk taking, but they can also result in greater damage in accidents due to their size. Larger cars also have a greater impact on the infrastructure, inflicting more damage to streets and requiring more space for parking. “It makes sense to tax cars in that way,” he said, “other countries such as the Netherlands tax cars based on mass.”
There are also potentially life-saving ramifications for planning infrastructure. Claus explained how making streets narrower will have a greater effect on risk taking for those in larger vehicles as they will slow down, lowering the risk they take.
On generalized risk taking there are many possible implications, such as on consumer decision-making. The car cushion effect may impact whether a person buys a lottery ticket or not in the gas station, or what kind of drink they purchase.
Methodology
The study consisted of two experiments. The first examined the effect of car size on driving behavior through tests in a realistic driving simulator. The second investigated car size effect on generalized risk taking, asking participants to consider car advertisements and additionally, testing their attitudes and behaviors toward risk taking.
