And while that heavy vehicle doesn’t improve your survival chances, it increases the odds of killing occupants in smaller ones
- While a large vehicle offers more occupant protection, there’s a point where going bigger doesn’t make a difference
- And while that bigger vehicle isn’t doing more for you, it’s increasing the risk to other drivers
- Airbags and other protection technologies are doing more than extra vehicle weight to keep occupants safe
“For American drivers, the conventional wisdom is that if bigger is safer, even bigger must be safer still,” said David Harkey, president of IIHS. “These results show that isn’t true today. Not for people in other cars. And – this is important – not for the occupants of the larger vehicles themselves.”
“Fleet average” is the average weight across all consumer vehicles in the market, from the smallest cars to the largest SUVs and pickup trucks, and it’s currently 1,814 kg (4,000 lbs). The IIHS’ research found that for vehicles that weigh less than the fleet average, the risk of its occupants being killed in a crash substantially decreases for every 227 kg (500 lbs) of additional weight.
In a nutshell, if you trade your smaller vehicle for another one that weighs 227 kg more but is still below the fleet average, your chances of survival increase. But the research also found that if your vehicle weighs more than the fleet average of 1,814 kg, one that’s even heavier doesn’t substantially increase your chances of survival.
On top of that, if a vehicle is below the fleet average, adding 227 kg more weight creates virtually no additional risk to the occupants of other vehicles in the crash – but if you add 227 kg to a vehicle that’s already over the 1,184-kg average, the danger to people in other vehicles increases.
The researchers examined two-vehicle crashes between 1- to 4-year-old cars, SUVs and pickups; and in the periods of 2011-2016 and 2017-2022. They found that crash compatibility – how the interaction between different vehicles affects the relative safety of the people in them – has continued to improve. For many years, SUVs and pickup trucks “posed an outsize threat” to people in cars, partly because the positions of their force-absorbing structures weren’t aligned. If these larger vehicles struck a car, they tended to ride up over the hood of the smaller vehicle, rather than striking its crumple zone.
Beginning in 2009, automakers began changing the front ends of their large vehicles to better align with the energy-absorbing structures of smaller cars. In addition, they also strengthened the cars’ structures, and added side airbags to all types of vehicles for protection in T-bone crashes. The IIHS said that largely due to these changes, SUVs and pickups are “substantially less dangerous to people in cars than they were earlier.”
Some SUVs and pickups in the 2011-2016 study predated the vehicle structural changes. In that period, car occupants were 90% more likely to die in crashes involving SUVs weighing more than 2,268 kg (5,000 lbs) than they were in crashes with other cars. Conversely, in the 2017-2022 study period, with more vehicles having undergone the structural changes, these heavy SUVs were only 20% more likely to result in fatalities to car occupants, versus car-to-car crashes. Pickup trucks were 2.5 times as likely to result in fatalities to car occupants over car-to-car crashes in 2011-2016, but that fell to a little below twice as likely in 2017-2022.
That said, now that these larger vehicles have structures that are better aligned to cars, “a greater share of the risk they pose to crash partners comes from their weight,” the IIHS concluded. At the same time, improvements to their airbags and other occupant protection technologies “mean that the relatively safety benefits of being inside a larger SUV or pickup have decreased.”
The weight of an average vehicle during the 2011-2016 period studied was 1,486 kg (3,277 lbs). In the 2017-2022 period, the fleet average had increased to 1,500 kg (3,308 lbs); it’s now 1,814 kg (4,000 lbs). The percentage of SUVs weighing more than 2,267 kg (5,000 lbs) actually dropped from 11% in the first study period to 7.4% in the second. Pickup trucks did the opposite: 91% of trucks in the first study period weighed more than 1,184 kg, but 97% did in the second period.
“There’s nothing magical about 4,000 pounds except that it’s the average weight,” said Sam Monfort, senior statistician at IIHS who led the study. “Vehicles that are heavier on average are more likely to crash into vehicles lighter than themselves, while the reverse is true for vehicles that are lighter than average. What this analysis shows is that choosing an extra-heavy vehicle doesn’t make you any safer, but it makes you a bigger danger to other people.”
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