San Diego’s Mission Valley East Trolley Extension
Sometimes an obvious decision can be very hard to make.
But a closer look at the details quickly brought up a series of incredibly difficult challenges, largely focused on how best to serve the university campus.
The Obvious Decision
San Diego State University sits perched on a mesa overlooking Mission Valley. It is the largest and possibly most crowded campus in the state university system, with more than 35,000 students, faculty and staff.
The campus has massive traffic and parking problems. More than 80 percent of the students commute to campus. While numerous bus routes serve SDSU, the topography and impacted neighborhoods surrounding the school make fast, direct routes difficult to create.
The layout of the campus quickly presented the first challenge to light rail. While the Mission Valley-Interstate 8 freeway corridor runs along the north side of campus, the school is oriented to the south — with the entrance to the campus and the transit station, as well as a planned redevelopment area, all on the south side.
MTDB faced a choice: Place a new trolley station on the north side of campus, among remote service buildings and down a steep hillside; or loop the tracks up the hillside, under a portion of the campus and to a new underground station at the centrally located transit center.
The “heart of the campus” choice seemed obvious, but it wasn’t. Major obstacles stood in the way.
The loop route required a tunnel to access the station. Technical limitations of light rail prevented it from reaching grade by the time it could be brought up out of Mission Valley to the campus transit station. MTDB had never designed, built or operated in a tunnel prior to the Green Line.
The route was longer, and would loop out of direction for through passengers. The detour south onto the campus would cost two extra minutes for passengers not getting off at SDSU.
The loop route onto campus was expected to cost up to $75 million more than the simpler, northern route. The environmental impacts of crossing canyons and tunneling under the campus were initially unknown. The surrounding community expressed concern that the trolley would bring unwanted traffic and activity to their neighborhood and initially opposed the loop route to the southern campus entrance. Instead, community members actively supported the northern route closer to the freeway. The constructability of the loop project was a concern. The route was high on hillsides above the freeway, and the geology of the tunnel area was unknown.
The challenges seemed to overwhelm the desire to serve the heart of the SDSU campus. The MTDB moved forward cautiously, keeping both options open. Several factors led to the eventual decision to take the more expensive and difficult route — but the one that would better serve transit riders.
A design panel of experts evaluated options for increasing ridership projections at the northern location close to the freeway. The panel concluded that to achieve reasonable ridership at a northern campus station, features such as raising the station to the height of the campus, moving the bus transit center to the northern location, and reconfiguring some of the campus to improve pedestrian connections to the station and to re-orient the campus toward the station would be necessary. All these features added significantly to the cost, and made the loop route appear to make financial sense.
A value engineering team analyzed the loop and tunnel option, recommending a longer, deeper tunnel that improved constructability, and reduced uncertainty and risk. A survey of SDSU students showed that they preferred the southern loop station site two-to-one over the northern location.
A project advisory committee of area stakeholders reviewed the options, identified modifications that would help address community issues, and recommended the southern route and station.
A Station Design Review Committee, also comprised of area stakeholders, actively provided input into the design of the SDSU Station, which reflects community and campus character and history through its architecture and public art.
