On Sunday, Dec. 3, motorists will encounter a series of short, intermittent traffic closures on northbound and southbound Interstate 5 near Balboa Avenue, between Pacific Beach and Clairemont. Lanes will be reduced to relocate overhead utility lines for the future Mid-Coast Trolley extension. Similar work and similar closures also will take place on Sunday, Dec. 10.
On both Dec. 3 and Dec. 10, the southbound I-5 lane reduction will begin at about 3 a.m., and end at about 10 a.m. the same day; a single lane going southbound will be closed for the duration of the work. 
The intermittent northbound and southbound traffic closures will occur for about 10 minutes each from approximately 6 a.m. to 8:30 a.m. Closures may be longer than 10 minutes, if necessary, to ensure public safety. 
The Mid-Coast Trolley Project will extend the Blue Line Trolley service from Old Town north to the University City community, serving major activity centers such as Mission Bay Park, the VA Medical Center, UC San Diego, and Westfield UTC. It will offer a one-seat (no transfer) ride from the international border and communities south of Downtown San Diego all the way to University City. Nine new stations will be constructed. 
The project will connect corridor residents with other Trolley lines serving Mission Valley, East County, and South County. It will tap the coastal area into the larger regional trolley/transit system, connecting hundreds of thousands of people with universities, hospitals, job centers, shopping, and recreational destinations.
Major construction began in 2016, with service anticipated to begin in 2021. The current budget for the project is approximately $2.1 billion.