Free rides on the subway will be offered by Metro to help area residents move around the region when the 405 freeway is shut down over the Sepulveda Pass on the weekend of July 15 to 17, agency officials said Friday.

In addition, Metro plans to run frequent weekday service on all its rail lines and the Orange Line busway that weekend. More buses will be running on key streets, including Ventura Boulevard, Sunset Boulevard, Santa Monica Boulevard and Fairfax Avenue. Only the subway will be free — regular fares will apply on other rail lines and Metro buses.

The Red Line subway offers a vital link between North Hollywood in the San Fernando Valley and downtown Los Angeles. Subway passengers can transfer from Red Line subway stations to bus service on major east-west streets to reach the Westside.

The 405 is being shut down for 53 hours that weekend for the partial demolition of the Mulholland Bridge over the freeway. The bridge is being rebuilt both wider and seismically stronger as part of the I-405 Sepulveda Pass Improvements Project that is adding a northbound carpool lane to the 405 between the 10 and 101 freeways and making numerous other fixes.

Metro, Caltrans and law enforcement officials are encouraging motorists to plan ahead for alternative routes, avoid the area or stay home. There is expected to be severe congestion throughout the area. More details are on this news release.

County Supervisor Zev Yaroslavsky — who is also a Metro Board Member — has a blunt post on the closure on his website. Excerpt:

Obviously, the best way to steer clear of the aggravation zone and reduce congestion is to stay home that weekend or make plans in the neighborhood, like catching a movie at the local theater. If you’re supposed to work, try to change your schedule, take a couple vacation days or telecommute.

If you must hit the road, chart a course using the region’s many other freeways. You may end up driving more miles, but I guarantee you’ll get to your destination faster than by gambling on 405 detours that could leave you stuck for hours.

For those of you who think you can outsmart this potential mother of all traffic jams, my advice is simple: save your gas. After representing the San Fernando Valley and Westside for more than three decades as a Los Angeles city councilman and county supervisor, I know virtually every shortcut in those parts—and none will work because of the sheer volume of vehicles being taken off the freeway.

A news conference on the closure will be held Monday morning. We’ll provide coverage at The Source and I am taking an educated guess that there will be a considerable media presence.

The latest detour maps for motorists are posted after the jump.

Click above for a larger image.

Click above for a larger image.