From the Monrovia City Manager's report:
Beginning March 9, 2013, California Avenue will be CLOSED to all traffic between Duarte Road and the area just north of the railroad tracks for 5 months, opening back up in July 2013.
Crews are constructing grade crossing improvements, expanding from one track to two for the Metro Gold Line Foothill Extension. Thru traffic will be permitted along Duarte Road across California, but traffic crossing Duarte Road on California will be detoured to Myrtle Ave or Mountain Ave. Sign up for construction notices at www.foothillextension.org.