It’s a fine philosophical point, but far from practicality when we’re still trying to keep these cars from accidentally running into things.

The trolley problem was never an argument against mass transit.

if the vehicle behind you is much smaller, like a motorcycle, so maybe your occupants don't even get whiplash, and the crushed motorcyclist would be considered at-fault

You’re describing tailgating. This isn’t even a trolley problem.

Jamming on the brakes for no reason is bad driving. Jamming on the brakes because something is in front of you is…that’s why we have brakes.