Sometimes there's nothing you can do to avoid an accident with another driver. You can get in a crash standing still at an intersection. In an accident, the biggest car will win. If the average car on the road was a Mini Cooper I wouldn't worry about it. But with the prevalence of SUVs, anyone driving something smaller than a crossover is taking a big personal risk.

From the research I've seen, that's not a significant factor. People aren't dying in their compact cars sitting at intersections. Sure, sometimes it happens -- and sometimes a semi or train hits you and even an SUV won't help.

According to the IIHS, for example, the little 2-door Honda Civic has about the same fatality rate as the safest large SUVs.

People in small cars aren't "taking a big risk". About as many people in America die of influenza as car crashes, so if you're driving an SUV but haven't gotten a free flu shot, I don't believe you're doing it out of some calculated risk assessment.

Flu deaths are concentrated on the very young and very old, though.

The fundamental connection: people who drive SUVs and people who skip flu shots don't care about externalities.

Indeed true that I'm extremely low risk for flu complications, though I live with someone at high risk, and should get flu shots now.

It's not that I don't care about externalities, but that I'm going to weigh them against direct concerns. It's true driving an SUV might have a small percentage impact on the environment. It's also true that it slightly increases my chances of killing someone else in an accident. But if it significantly decreases the chance the person killed in said accident is my wife/kid, I'm going to prioritize that over the "dangers" SUVs provide to others.