DEVELOPING A CALIBRATED TRANSIT MALL SIMULATION OF BUS AND LIGHT RAIL OPERATIONS FOR CONCEPTUAL PLANNING

The South/North Transit Corridor Study Draft Environmental Impact Statement (DEIS) has evaluated transit alternatives that would combine light rail and bus operations through downtown Portland on the Transit Mall. The Transit Mall, an innovative bus transit facility, concentrates downtown bus operations onto two one way north/south streets with specific transit operating rules. Two continuous bus only lanes allow buses to load in the right lane and pass each other in the center/left lane. A discontinuous third, left lane, facilitates local automobile circulation. The DEIS has examined the introduction of light rail in the bus passing lane with left-side platforms. Both Tri-Met and the downtown Portland community have questioned the impacts of light rail on overall transit capacity and performance with the proposed configurations.