Making bigger cars lighter can have more benefits than making lighter cars bigger
The notion that larger vehicles provide more safety in a crash is widely accepted, but new research from the Insurance Institute for Highway Safety (IIHS) challenges this assumption.
In brief:
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Larger vehicles do not always offer more safety: The study by IIHS reveals that while smaller vehicles benefit from added weight, once a vehicle exceeds the fleet average weight, the additional pounds provide minimal benefit and can increase risks to other road users.
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Weight impacts crash outcomes: Adding 500 pounds to lighter-than-average vehicles reduces the risk of death for occupants, but the same increase in heavier vehicles raises the risk to other vehicles' occupants.
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Improvement in crash compatibility: Design changes since 2009 have improved the compatibility of SUVs and pickups with smaller vehicles, reducing the risk they pose to car occupants.
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Call for lighter, more efficient vehicles: The study highlights the importance of reducing unnecessary weight in larger vehicles and improving vehicle designs to enhance safety for all road users.
About the study
While its true that smaller vehicles can benefit from the added weight of larger cars in terms of crash protection, there is a clear ceiling to how much additional weight contributes to safety. Once a vehicle exceeds a certain weight, the additional pounds provide little to no benefit for the vehicles occupants, and can pose risks to people in smaller vehicles.
The research, which studied crashes involving 1- to 4-year-old cars, SUVs, and pickups, finds that adding weight to lighter-than-average vehicles significantly reduces the risk of death for the vehicles occupants.
For every 500 pounds added to these lighter vehicles, the risk of death drops substantially. However, this benefit levels off for vehicles that weigh more than the average. Once a vehicle surpasses the fleet average, adding more weight does not further reduce the death risk for the driver.
A danger to others
Interestingly, while adding weight to lighter vehicles helps reduce fatalities for those inside, it increases the risk of death for occupants in other vehicles involved in the crash.
For instance, adding 500 pounds to a heavier-than-average vehicle such as an SUV or pickup increases the danger for other vehicles on the road. This insight helps paint a clearer picture of how size and weight affect the safety of not just the driver but also other road users.
Crash compatibility improvements
The IIHSs study also examined how crash compatibility has improved over time, particularly regarding SUVs and pickups. Historically, these larger vehicles were far more dangerous to people in smaller cars because their design was not compatible with the smaller vehicles' crumple zones.
However, since 2009, automakers have worked to modify the front ends of SUVs and pickups to better align with smaller cars. These adjustments have significantly reduced the risk posed by these larger vehicles to people in cars.
For example, in the 2011-16 period, SUVs weighing over 5,000 pounds were 90% more likely to result in fatalities for car occupants than other cars. However, by the 2017-22 period, the risk had dropped to 20%, thanks to these design improvements. Similarly, pickups, which were 2.5 times as likely to result in fatalities for car occupants during the earlier period, saw a reduction to just under twice as likely in the later period.
A little lighter is better
Overall, the study emphasizes that while larger vehicles have advantages in some crashes, they are not inherently safer, especially for other road users. The IIHS's research underscores the importance of vehicle design improvements, including better compatibility between different types of vehicles, and a reduction in unnecessary weight for larger vehicles to prevent them from becoming a danger to others.
As the average weight of cars and SUVs continues to rise, the safety benefits of lighter, more efficient designs could become even more crucial for overall road safety.
Photo Credit: Consumer Affairs News Department Images
Posted: 2025-02-05 18:51:12
