Likewise, secure heavy items in the cabin when possible.

> As luck had it that day, it was the buckled man's skull which cracked, leading to his death a few hours later.

Situations like this make me wonder if some kind of helmet would be advisable for use in cars, and not only in bikes and motorcycles.

I don’t think a helmet would be all that helpful. For a person wearing a seatbelt in a modern car with airbags, there really isn’t a lot of hard things to hit your head against.

In these situations, the biggest damage to the brain is something called diffuse axonal injury where rotational forces from the sudden acceleration and deceleration cause injury to the neurons. A helmet would not protect you from that.

Really? I would have thought that heads smacking into side windows would be pretty common.

I know someone who was killed by this exact situation. No other injuries (that I'm aware of) for anyone else in the car. Their skull was broken

Modern vehicles have side curtain airbags to mitigate exactly that.

Not everywhere in the world. In poorer countries car manufacturers and regulators have perverse incentives to cut costs on safety devices, to be able to sell for a poorer clientele. For example, in Brazil up to 2009 airbags were not even mandatory, and when the regulations finally required it, they were under fire for several years. Today airbags other than the frontal ones for driver and passenger riding shotgun are still uncommon here. See https://apnews.com/article/ac0ec2592da24f2bb6386b58d0db074f

Helmets can come with their own issues like added weight and neck injuries, but the inconvenience means no one outside of Motorsport will use them.

I'm aware of the neck injuries, so the "some kind of helmet". When people hear about helmet usage in cars, people automatically picture in their heads drivers wearing F1-like helmets, or motorcycle-like helmets. But just like bike helmets are different from motorcycle helmets, car helmets would also be different, possibly lighter, to avoid neck injuries. Most law-abiding citizens aren't crashing over 200km/h to need massive helmets coupled to HANS devices like F1 racers.

My physics professor in college would wear a bicycle helmet when driving around in his minivan. The rumor spread in class pretty quickly the first time a student saw him doing that. The general sense of the rumor was, "Our prof is some kind of a freak."

His wife also left him in the middle of the semester. Another rumor was that she just couldn't stand his eccentricities any longer.

Personally, as a cyclist, I have had my helmeted noggin slam against the pavement on more than one occasion. I have come to greatly respect the potential injury that you could get from a collision at high speed. In hindsight, I can fully respect my physics professor's decision to wear a bicycle helmet when driving his minivan around town. In fact in the future if I find myself needing to drive in inclement weather, I may very well start wearing my bicycle helmet in my car. Hope my wife doesn't leave me.

I remember reading something to the effect that mandatory motorcycle-style helmets for all car passengers would significantly reduce the road toll but the inconvenience made it too difficult to implement.

No, just make sure that everybody is properly buckled.

The idea is not replace seatbelts or airbags with helmets, but to have an additional safety layer.