Poorly thought-through numbers

Peter Gordon notes this statement, from Secretary Ray LaHood’s blog, the Fast Lane:

In fact, each 1% of regional travel shifted from automobile to public transit increases regional income about $2.9 million, resulting in 226 additional regional jobs. Other economic benefits include increased productivity, employment, business activity, investment and redevelopment.

I wish he’d give a citation so that I could see where this came from, but let’s just think about this for a second. The yield of moving 1 percent of mode share to public transit is $2.9 million in personal income, which is probably more a reflection that transit mode shares are higher in metropolitan regions where incomes and regional products are also higher (as in, mode share isn’t a cause, it’s an effect). But even so…let’s think. So in Los Angeles, it cost us $875 million to build the Blue Line; it takes $65 million a year to operate it. That’s one line. Our subway costs us $92 million a year in operating costs; the other two light rail lines cost us over $40 million per year. We currently run about 2 percent transit mode share. Benefit numbers without cost numbers don’t mean anything, and vice versa. And this random number that LaHood relates doesn’t make transit look particularly good.

If we want to make the case that transit is good for cities, we can make those arguments. I am sympathetic to the idea that many of those benefits are not readily quantifiable. But….dang.