Red Hill is closed to all traffic over the 405 for repairs to the bridge and surrounding structure. Bikes cannot get through. Current information from the cities say that it will be closed through December 2016 with off-and-on closures into 2017.
Because this is between the 55 freeway and John Wayne Airport there are no good bike-friendly detours nearby. Your best bet is to modify your route to go east of the airport using Irvine Avenue/Campus and Von Karman.
