The difference is the cost. Public transport has superior fuel, space, and materials usage.
Another difference is that public transport is a known working solution which has been implemented with great success in many cities since the 19th century. While driverless cars is something we just now is getting the technology to build so it is untested.
Another difference is that public transport is a known working solution which has been implemented with great success in many cities since the 19th century. While driverless cars is something we just now is getting the technology to build so it is untested.