This recent Streetsblog article about the possibility of turning the M Ocean View line in San Francisco into a kind of subway is a good reminder about the always important connection between transit investment and density. The question I always pose to myself is, “If I were a private company deciding where to spend the money on a new and expensive subway line, what would I look for?” Most of us recognize that population and employment densities would be near, if not at, the top of the list.
Of course, if the company were fully private, then we would run the risk of low-density / unprofitable areas of the city not being serviced by transit. For a variety of reasons, that’s not an ideal outcome, which is why transit operators are mostly subsidized. The challenge is that the way we plan transit in most — or all? — cities has become so highly politicized today. That’s how we end up with the wrong transit technologies in areas that don’t have the density to properly support them.
Now, I don’t know the specifics of the M Ocean View line. (Maybe some of you do and will provide those thoughts in the comments below.) So this is not a post about what may or may not be appropriate in this particular instance. But it is a commentary on the importance of fiscal prudence and sound transportation planning.