La Jolla Colony Drive was closed for a full day for preparations associated with the construction of a Trolley underpass. This underpass will allow the Trolley to pass under La Jolla Colony Drive as it travels along the eastern side of Interstate 5. The future Trolley underpass will look similar to 70th Street, used by the Trolley Green Line.

Major construction is scheduled to begin on Monday, March 18. Due to the complexities of this construction, work is expected to continue through late 2019.

During construction, La Jolla Colony Drive will provide one lane of northbound and southbound travel. La Jolla Colony Drive is scheduled to be reconfigured on Sunday, March 24. At that time, southbound lanes will be closed, and northbound lanes will be re-striped to allow one lane of travel in each direction.

Occasional full weeknight and weekend closures may be required during construction; advanced notice will be given prior to each closure. During closures, there will be no access to La Jolla Colony Drive from east of the I-5 on- and off-ramps to Rosenda Court. Closures are currently scheduled to take place Monday, March 18, to Thursday, March 21, from 9 p.m. to 5 a.m. each night.

The Mid-Coast Trolley Project will extend 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 University Town Center. Nine new stations will be constructed. Major construction work began in 2016, with service anticipated to begin in late 2021.

Freeways and arterials in the Mid-Coast Corridor are generally congested and traffic congestion is projected to increase as the region grows. Population in the entire corridor is forecasted to increase 19 percent and employment is forecasted to increase 12 percent by the year 2030. The Mid-Coast Trolley extension will expand transportation capacity in the corridor to accommodate existing and future travel demand, particularly for peak period commute trips. The Mid-Coast Trolley will provide an effective alternative to congested freeways and roads for travelers and will reduce vehicle miles traveled.