Earlier quoted context omitted.
> The economies of scale you get by packing people in larger vehicles mostly have to do with the cost of fuel and staffing. Trains (and train-like options such as metros) are vastly more efficient than cars in number of people moved per unit of time per area used. That might not be a big deal in suburbia, but in dense inner cities it's one of the most important drivers of public transport.
Autonomous vehicles could chain up or drive really close together and achieve similar space efficiency. Also, if you look at a train track. It's mostly empty space with a train passing occasionally. Very different than a well used road. And autonomous vehicles could collaborate to counter any congestion. What makes trains efficient has more to do with the cost of energy and drivers than anything else. Both of those g…
A random crappy light rail line will do the equivalent of 5 lanes of traffic (each direction). A serious subway more like 20.
https://visual.ly/community/Infographics/transportation/solu...
Even if you run cars with no distance between the bumpers you'll still need room for changing lanes, crossing and the line.