Earlier quoted context omitted.
The thing you're describing is called a train.
Are you going to having a train running every few minutes to really make the delays comparable? And you need a fleet of rental cars so that people can actually get to their destination. What's the relative cost of all that vs. pavement?
Though your train of cars would likely have such low passenger density that a series of buses would be just as good. Special lanes just for buses are already a thing.