The popular San Diego holiday celebration December Nights is expected to cause traffic delays this weekend.
The 40th edition of the holiday spectacular returns to the San Diego's Balboa Park on Dec. 1 and 2.
More than 350,000 visitors are expected at the two-day event, which includes free admission to Balboa Park museums from 5 p.m. to 9 p.m.
Caltrans warned motorists in the Balboa Park area to expect delays, particularly on state Route 163 and Interstate 5, due to the event.
On Friday night, traffic maps of both major freeways showed heavy traffic backup. Use NBC 7's traffic map to check for delays.
San Diego Metropolitan Transit System (MTS) said bus passengers should expect delays near Balboa Park as well.
Bus stops on Park Boulevard from University Avenue to C Street will be closed Friday from 4 to 11 p.m. and Saturday from 1 to 11 p.m.
The closure will impact routes 1 and 10. Route 7 and Rapid 125 will be detoured to state Route 163.
December Nights will have free event shuttles leaving from downtown for people looking to take public transportation.
MTS has more information on impacted routes and stops during December Nights.
December Nights started in 1978 as part of "Christmas on the Prado" in Balboa Park, a small holiday celebration put together by a dozen institutions along El Prado. The crowds and event grew over the decades and, in 2002, it was renamed December Nights.
It continues to be the largest free community event in San Diego. Find out more about the event here.