When I sat in on one of Jarrett Walker’s courses in network design two months ago, Walker had his students playing a game. A transit consultant, Walker helps cities pick the routes of buses, streetcars and trains. In the game, the students had to design a bus system for an imaginary city called Newport. They learned to evaluate tradeoffs between ridership and coverage, between waiting and walking. They saw how different patterns — gridded like a chessboard or centered like an asterisk — favored different journeys.
What Walker can’t teach them is politics: the ways in which developers, elected officials and neighborhood groups nibble at the systemic logic of transit design to feed their own interests. Outside the classroom, alterations to transit networks come piecemeal, an addition here or a subtraction there, sufficiently small to slide through the gaps in the political fabric. Walker calls it “pruning.” Newport is a fake city; in real life, redesigning a full urban transit network for a major city is a once-in-a-lifetime opportunity.
But that is exactly what Walker has been doing for the past eight months in Houston. Along with the consultancy Traffic Engineers Inc. and local transit planners from METRO, Walker was given carte blanche to redesign the bus network in America’s fourth-largest city. Side by side with the present network, the new scheme is a virtually unrecognizable revision. It will transform how the 3.5 million people in the METRO’s Houston service area travel without a car.