Excellent ideas. In the US, metropolitan rail transit systems need a dramatic reimagining. They are expensive, slow, and often crime ridden. Would love to see their right of way put to better use.
We should rip out the train tracks, put down asphalt, and convert them to car tunnels, but to be used only by people driving one specific brand of car.
You joke, but a dedicated lane for self driving vehicles (either privately or publicly owned) could be lower cost and better utilization of the resources.