Walkin' the Line

I’ve been stewing about the Central Corridor light rail line in Saint Paul. When officials came to their senses (somewhat—no full credit from me until we see the actual results) and announced on Tuesday the possibility of three more stations, I felt reprieved from writing a post on this subject. Alas, I can’t stop myself from weighing in.

It was determined, based on a federally-required cost-benefit calculation, that the spacing for certain stations along University Avenue would be one mile apart. These particular stations happen to be located in the lowest income, most transit-dependent neighborhoods. This means up to a half mile walk, if you live on University or another street intersecting the station. For some, the walk can be even longer. Planners like to draw circles with stations in the center, showing the ½ mile service area. But that’s as the bird flies. If people had wings they wouldn’t need the rail line.

The logic behind the mile-apart decision was that the rail line must meet federal standards for cost-effectiveness. Not a bad idea, although it creates some strange incentives, as highlighted by Net Density. But why was the decision made to space these stations more widely in order for the line to qualify as “cost-effective?” I hunted around quite a bit, and could not find the answer to that question.



So I went straight to the source and looked at the how the calculation of cost-effectiveness is made. I reached this conclusion: the cost-effectiveness modeling is done in a black box that few people know or understand. Quantitative models, by virtue of being number-oriented, masquerade as technical and objective in nature. But we shouldn’t fool ourselves; they are in fact laden with values (and other non-data-driven assumptions), values that are never made explicit because they’re buried in complicated numerical formulas.

The evaluation criteria for the stations included nine considerations, and as the transportation planners like to point out, “transportation service equity was not a criteria” (sic). It’s not just that equity was not a criterion; the criteria themselves were weighted against an equitable outcome. The criteria included considerations such as proximity to major employment centers and development potential. Lower income neighborhoods are often lower income precisely because they lack these attributes.

The cost-effectiveness calculation itself gives preference to some transit users over others (namely, the majority by virtue of being the majority) under the guise of a supposedly objective measure. Cost-effectiveness is a function of total user-benefits, measured as mobility improvements for all transit and highway users. A 2005 survey by the Met Council showed that half of LRT users would have made their trip by driving alone if LRT had not been available. A little more than 20% said they’d take the bus, and just under 10% said they couldn’t make the trip. Using aggregate benefits tilts the index towards the needs of people who would otherwise drive because they are the biggest share of the aggregate. Moreover, the benefits for drivers derive from different factors than the benefits for non-drivers. The benefits for drivers, who walk little or not at all, don’t wait, and don’t transfer, come from faster train times. For those reliant on transit, however, the opposite is true. Their total travel time is very long—they walk, they wait, they transfer.

So the calculation works like this (illustrative example). Suppose there are 100 drivers, and their travel time is five minutes faster because of fewer stations. This totals 500 minutes in benefits. Twenty people who could not make the trip without transit walk 20 minutes more with fewer stations (400 minutes in benefits.) Five hundred is more than four hundred. The drivers win.

I understand that getting people out of their cars is important, and that there are many different views on this subject. But let’s not pretend that the design and calculations are an impartial, objective, “best” way to do transit, stripped of value judgments. Kudos to folks like the District Councils Collaborative, the Alliance for Metropolitan Stability, and the Central Corridor Funders Collaborative for their efforts in getting decision-makers to acknowledge that.

Notes: thanks to the many readers who emailed me with comments on my first post. You made great points! Don't be shy--share them!