2008 OCEA Finalist


Mission Valley East Light Rail Transit Project

Mission Valley Light RailThe Mission Valley East Light Rail Transit Project (MVE LRT) opened to the public on July 10, 2005. It created a Green Line by closing a 5.9-mile (9.5 km) gap between the Blue and Orange Lines in San Diego’s trolley system. Twenty-five years ago the San Diego Metropolitan Transit System envisioned the $506-million project to provide residents with increased mobility within the busy Interstate 8 (I-8) corridor.

The project’s tunnel section, through the San Diego State University (SDSU) campus and its underground station, was constructed using soft-ground New Austrian Tunneling Method (NATM) techniques. The campus is located on significantly higher ground than Mission Valley and is quickly approaching capacity. Right-of-way impacts throughout the area were significantly minimized using a combination of NATM and cut-and-cover tunnel designs. At the time of construction, NATM had not been used significantly in North America. Teams of engineers from the United States and England, who had designed the Channel Tunnel or “Chunnel” linking the United Kingdom and France, were brought in to design the Mission Valley tunnel.

In addition to its tunnel portions, the project included construction of eight bridges—totaling more than two miles and four stations, including the SDSU underground station. The new guideway alignment required significant retaining walls, a U-section and a one-mile long triple-cell box culvert.

In addition to its innovative uses of technology and construction techniques, the MVE LRT significantly enhances the transportation capacity and mobility within the I-8 corridor. By 2015, the system is on track to attract 11,000 boardings per day. With more than 2.5 million new riders expected in the metropolitan area by the year 2015, the project will be a boon to transportation within the busy I-8 corridor.