The Making of a Restructure: Downtown Seattle

Even if all King County Metro’s “commuter” bus routes were shunted to Link Stations, downtown Seattle would still teem with buses. Many of the transit routes that run entirely within Seattle serve downtown, converging on Third Avenue to create a transit mall. In this proposal, as with past ones, this stretch of road would go from having the greatest amount of bus traffic in the city to being nearly devoid of it. But why mess with this longstanding feature of Seattle’s transit network?

The answer lurks underground. The Link runs beneath 3rd Avenue, and between Westlake and Stadium Stations its stop spacing is close enough to not require infill service. The project of moving people through downtown would cease to be a joint bus-Link mission and rest solely with the latter. For some, this could introduce a transfer when one wasn’t needed before. That may be less convenient, but there is an opportunity cost to the present use of resources. Moving people through downtown using a litany of buses burns in-service time without a commensurate access gain. Consider this access-per-segment map of Seattle. Contrast the segment journeys per trip measurement and segment journeys measurement for the segments along Third Avenue in downtown Seattle. The high score under the latter measurement, and the low score for the former indicates that while many transit trips rely on this segment, it’s taking a disproportionate service investment to accomplish this. Meanwhile, the 1 Line’s downtown segments maintain high performance in both measurements. Terminating bus routes short of downtown, and connecting them to 1 Line stations, allows resources be reinvested in areas where it could generate stronger access gain.

Truncating routes to stop once they reach downtown Link stations yields some strangeness—I view this arrangement only as an interim step toward a more thoroughly restructured network. Routes that once went through downtown now exist in two disconnected, but identically-named, segments. In the case of route 2, the savings seem almost performative: service is only eliminated between a single pair of stops. Suboptimal in a different way is route 21. It could be a candidate for a more severe truncation, but its present stop pattern hinders connecting it to Stadium or Chinatown stations bidirectionally. Nevertheless, this interim network provides a useful piece of information: a lower bound on how much in-service time would be freed in a retreat from downtown.

Using the same frame of reference as the previous post, the 1,603,434 total seconds of savings is over 1.5 times the amount of service required to operate the 1 Line within King County. With the two changes combined, there are over 2.5 1 Line’s worth of transit service to be reinvested. That’s almost 8.5% of the total time expended by all transit service on a weekday in King County freed up for reinvestment. Is that enough to engineer a network that improves the prospects of transit riders navigating Seattle, regardless of where they’re starting, where they’re going, whatever the time of day? The next installment will do that accounting.