King County Metro bus, flickr user pdxjeffKing County Metro, greater Seattle’s main transit agency, is in a budget pickle.  The recession has trimmed the agency’s sales tax receipts; the decline in gas prices—at least compared with 2008’s sharp spikes—has eaten into ridership and farebox revenues; and labor costs keep inching up. 

The 1-2-3 punch has knocked Metro back on its heels—and, like many transit agencies across the country, Metro is considering cutting bus service to remain solvent. Of course, the natural instinct for the politicos who oversee Metro is to treat service cuts as a political decision, not an analytical one.  With political decisions, officials choose service cuts by asking themselves “who’s going to scream the loudest?”   The tendency is to spread the pain around, cutting service a little bit everywhere—even if it means trimming relatively productive routes and sparing routes that aren’t doing as well.

But I’d argue that Metro should take a more analytical approach:  if it’s got to cut service, it ought to cut the routes that are the least productive — particularly those that don’t attract many riders or offset much car travel.  That can lead to some politically contentious decisions—such as cutting bus service to wealthy, politically active neighborhoods.  But in my view, it’s the honest and responsible thing to do.

Metro rides per hour, 2008, peak busesLuckily, Metro is awash in data to use for this kind of analysis.  Take, for example, this chart, taken from 2008 route-by-route ridership data for peak route buses. (Click it for a larger version.) Each dot represents a single route or major route-segment that runs during peak hours.  The higher up the dot, the more riders the route carries per hour. The routes with lots of riders per hour are the stars, and the routes with only a few riders are the stinkers.  So if your goal is to minimize the impact of service cuts on actual riders, you save the stars, and cut the stinkers.

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  • Clearly, there are stars and stinkers throughout the 3 different regions that Metro serves.  But if you look carefully, the routes in the West subregion, which includes Seattle, have far more stars, and fewer stinkers, than the East.  The South subregion lies between the two.  So if you were basing your cuts on how productive the routes are, you’d find that a disproportionate share of the “stinker” routes, at least by this metric, are in the East.

    But that means that if you’re a politician representing a jurisdiction in the East subregion, you’d be tempted to argue against using route productivity to gauge service cuts.  You’d be more inclined to cut equally from all subregions—even if that means cutting more deeply from productive bus routes serving Seattle and Shoreline. 

    And that’s basically where the debate stands right now.  Metro’s structure and governing rules pit the three subregions against one another.  So rather than focusing on maximizing the productivity of the bus system as a whole, some officials are focused on protecting their home turf by arguing, in effect, for deeper cuts from productive routes in other subregions.

    There’s a lot more to be said about all of this—and I’m sure I’ll have more later.  But it’s odd to me that it’s taken so long for the idea that Metro should use productivity metrics, rather than arbitrary rules (like the infamous 40-40-20 rule that has targeted service increases to the places where existing ridership is low) to guide basic decisions about where and how often buses should run.  For a system that serves up over 110 million rides per year, even a small improvement in efficiency can mean millions of additional transit rides served, without adding any new buses or bus drivers.  A focus on improving service efficiency would have been every bit as welcome when the economy was booming as it is now that times are tough.

    Bus photo courtesy of Flickr user pdxjeff, distributed under a Creative Commons license.