Driving a vehicle of increased size and weight only improves car crash safety to a point, the Insurance Institute for Highway Safety or IIHS said in one of its latest studies, though these vehicles are considerably more dangerous to smaller vehicle occupants.
Safety benefits in a car crash increase when the lighter vehicles’ weight moves closer to the fleet average of 4,000 pounds, the study indicates, but above that level additional benefits drop off sharply.
If a vehicle weighs below 4,000 pounds, every 500 additional pounds closer to that threshold cuts the number of driver deaths by 17 “per million registered vehicle years.” Once it passes the average, however, adding more weight has drastically less safety benefits for the occupants of the large, heavy vehicle – only one less death per 500 pounds.
Meanwhile, a collision between a 500-pound heavier vehicle and a smaller, lighter one causes only one more death in the smaller ones. Vehicles adding weight above the 4,000-pound average cause up to 7 more deaths in smaller vehicles during an impact. In effect, surpassing the average offers only slight survivability improvements for the vehicle owner, but comes at the price of fatal danger to occupants of lighter vehicles.
Chart provided by the IIHS
Since 2009, automakers have also been designing their vehicles to lessen the fatality of car crashes between larger and smaller vehicles. Smaller vehicles have better safety systems, including abundant use of airbags from multiple angles. More subtly but just as effectively, full-size SUV and pickup front ends have been redesigned to engage with smaller-vehicle structure rather than riding up over the hood to strike occupants directly.
While there clearly still are car crash safety benefits for larger vehicles, this drops off sharply after a certain threshold. IIHS senior statistician Sam Monfort claims that “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.”
SUVs and pickups show an interesting difference as well. SUVs gain significantly more car crash safety (13 less deaths per 500 pounds) through increasing size up to the 4,000-pound average, and thereafter become slightly more deadly to their own occupants (1 more death per 500 pounds), but are relatively harmless to smaller vehicle occupants (1 or 2 extra deaths per 500 pounds).
Pickups, by contrast, offer slight car crash survivability advantages at any size (1 less death per 500 pounds), but are much more dangerous to occupants of smaller vehicles than SUVs – causing 4 more deaths per 500 pounds under 4,000 pounds, and 7 more above that weight. Effectively, pickups offer marginal extra protection at best, but are the deadliest vehicles on the road to other drivers.
David Harkey, IIHS president, concluded that “these numbers show that transitioning to lighter pickups could have big benefits too, especially since many drivers don’t use their trucks for carrying heavy payloads.”
Comments
The safest vehicle is one that never crashes. A 1973 Pinto that never crashes is one heck of a lot safer than any new car with a gillion airbags and “avoidance” systems that crashes.
Well put ! There is a lot more involved with car crashes and injuries then just the size and weight of any one vehicle. Mr. Harley pointed out down sizing a particular vehicle would be an answer. So would down sizing home with 12 bedrooms
for millionaire that only uses 2 bedrooms. Energy efficiency would be much lower.
Someone forgot to talk about EVs they all weigh over 5,000 pounds up to 9,000 pounds. So you should be adding never to buy one because you will die in a crash.
Sorry, but whatever AI you used to collect your info ain’t very “I.” My Chevy Bolt EUV Premier weighs 3,680 lbs. And it has 10 airbags. The 2019 Bolt I had before it weighed 3,563 lbs. And the 2025 front-drive Equinox EV weighs 3,428 lbs. Other EVs under 5K lbs. include the Audi Q4, the Volkswagen ID3 and .4, Tesla models 3 and Y and several versions of the Model , Hyundai Ioniq 5 and Kona, Mazda MX-30, Citroen e-C4, Kia e-Niro, e-Soul and EV6, Nissan LEAF, Mercedes EQA 250, Lexus UX 300e, and many others, all the way down to the Mitsubishi i-MiEV. And in every case that’s with a full load of fuel! ;-])
I appreciate the IIHS’s senior statistician for explaining this study in one succinct paragraph:
“There’s nothing magical about 4,000 pounds except that it’s the average weight,” said Sam Monfort, a senior statistician at IIHS and lead author of the study. “Vehicles that are heavier than 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.”
Richard P, I remember when insurance companies were trying to surcharge people with larger and heavier vehicles because their theory was, they are dangerous to people driving lighter and smaller vehicles.
I believe that is convoluted ass backwards thinking. If you’re smaller and lighter vehicle is more dangerous in these accidents they are the ones that should be paying an insurance surcharge. This is not rocket science or some revolutionary concept. It is simple physics.
The automotive industry has also developed crumple zones in vehicles to reduce the G-forces on the human body during a crash. For the most part the concept works fairly well.
Not so much when the driver winds up in the back seat with the engine in his lap.
When I was in high school, in the 60s, I looked at a car that four intoxicated young men had crashed an Olds Cutlass into a tree at 100 Mph. Oddly the body of the car stayed mostly intact, the engine was hurled about 60 ft. away. The speedometer was jamed at close to 110. The radio was ejected from the dashboard as if it were spit out. All four occupants were killed with two decapitated. After the victims were removed the State Police put the car with body fragments and completely blood soaked interior on display as a warning. “SPEED KILLS”! I took that warning to heart. Cars don’t cause accidents, drivers do.
Sorry but this story is cherry picking.m
Mass, size, design are the three factors at play. The design part is the critical element.
You can make a small car safer via design. Same with full size. But when on equal term mass generally wins.
I was recently struck head on in a mid size truck by a Rav 4. I drove home She did not.
Speed of the mass can matter too. You just can’t do this on size and weight only.
How about inserting a 10,000 lb. Hummer into the equation? I’d hate to see/here what would happen to the 4000 lb. vehicle. TBD
Lenny, How about inserting an 80,000 lb. tractor trailer. People need to take their face out of their cell phones and pay attention when they’re driving. Driving a car isn’t something you do while you’re busy doing something else.