I use the roads around Boston just about every way imaginable. I walk, run, bike, ride a motorcycle, and drive a (fairly small) car. In recent years, I’ve been alarmed to notice the size of the average automobile growing larger and larger. Vehicles like the ridiculously-but-aptly named Nissan Armada and the GMC Yukon feel physically threatening, and indeed, the increased height of hoods on vehicles like these really is a danger. The supersizing of American vehicles has significantly increase pedestrian deaths.

If I eventually get flattened by an oversized motor vehicle, you will not find my corpse looking surprised. The worst part is that absent government intervention, the rational choice for any one individual is to buy their own behemoth, so as to protect themselves and their vehicle’s occupants from the other tanks on the road. That just leads to more giant cars on the road, and then to ever larger giant cars.