At Human Transit, Jarrett Walker answers a reader question about whether SDVs (self-driving vehicles) will eventually replace some or all transit. Read the whole post, but here is an excerpt.
So to sum up, the technophile urbanists who believe that self-driving cars will eliminate the need for public transit are making several mistakes:
- They are assuming that technology will change the facts of geometry, in this case the facts of urban space.
- They are assuming that the costs of having every passenger encased in a metal sphere (in terms of production energy and emissions) are readily absorbable by the planet. (To be fair, the SDV discussed here is one that you don’t own but just grab when you want it, so if it replaced the car there would be far fewer cars. But that’s different from replacing a bus.)
- If they think that self-driving cars will replace buses but not rail, then they haven’t informed themselves about the vast diversity of different markets that buses are used to serve. Self-driving cars many logically replace some of these markets but not others.
- They believe that public transit is incapable of improving in ways that make it more positively attractive to a wider range of people, despite the fact that it is doing so almost continually.
Again, the whole bus vs rail confusion here arises from the fact that technophile urbanists classify transit services according to how they look and feel, whereas transit experts care more about the functions they perform.
So yes, buses are currently doing some things that other tools could do better, especially in sparser markets. Some agencies, like Vancouver’s, already have the tools to solve that problem. But when a huge mass of people wants to go in the same direction at the same time, you need a rail if you have tracks and an exclusive lane for them, or a bus if you don’t. I don’t care whether it’s rail or bus, but the need for a high-capacity vehicle running high quality service that encourages people to use space efficiently — that’s a fact of geometry!
I think I agree with all Walker’s points, except maybe that he oversimplifies the geometry argument. Couldn’t we have self-driving microbuses taking the place of low volume routes? Walker states this is a legacy problem with unions, which could be solved without robot cars (but of course, hasn’t yet).
Also, his geometry argument ignores carpooling. If I could sign up for robot dial-a-ride service and I could choose a higher price to ride alone or a lower price to ride with other commuters, I imagine many people would choose the carpool option (especially existing transit riders). Theoretically, routing software could calculate who your carmates would be based on your origin and destination, and you would arrive at your destination slightly slower than the ride-alone subscription (hence the lower cost). This imaginary system makes the “geometry” argument less valid.
Of course, such a system is a long ways off. We will still of course need transit for a long time, and as Walker states, transit agencies are making efficiency and attractiveness improvements all the time.