It needs to be based on the number of passengers, though. 3 people in the car should be free in all circumstances. 2 people in the car should be free sometime

It needs to be based on the number of passengers, though. 3 people in the car should be free in all circumstances. 2 people in the car should be free sometimes, but pay a very small fee when the road is very congested. 1 person should always pay a fee. Sometimes small, sometimes large, depending on traffic. 0 people in the car (in the case of autonomous cars) should always pay a phat fee. This is the only thing that will prevent driverless cars from ruining our awesome road infrastructure in America. If we don't do this, driverless taxi companies will have cars polluting and congesting every public road trying to be capture a ride until they're clogged and useless.