Mass transit is what I had in mind.
Personally, I prefer the car. But if I had to bear all of the costs of using a car directly, and urban sprawl were not so preferred by planners, mass transit would be my choice more often.
This is especially true at rush hour. Most highway construction happens just to serve rush hour traffic, a time when mass transit is at its most efficient.
If these subsidies did not exist, mass transit would be much more widely used. There'd be many more choices and there'd be no need to subsidize mass transit.
We actually have subsidies to counter the negative effects of other subsidies. Getting rid of all subsidies would be better and allow people to make the right choices for them with fewer negative side effects.