Ramp Jam on the 405 continues with a 90-day closure of the eastbound Wilshire on-ramp starting Thursday, August 22. Here’s the press release from Metro:

Rebuilt On-Ramp to have Nearly 300% Greater Capacity

The I-405 Sepulveda Pass Improvements Project contractor is scheduled to begin a 90-day closure of the eastbound Wilshire Boulevard on-ramp to northbound I-405 in West Los Angeles beginning Thursday, August 22, 2013.  It is the last extended ramp closure that will be required for the Wilshire Interchange, as well as the last of its kind for the entire freeway improvements project.

Motorists who normally utilize this on-ramp to access the northbound I-405 from eastbound Wilshire are encouraged to plan ahead to determine alternate routes, allow extra time to reach destinations, eliminate unnecessary trips to avoid peak congestion and/or consider ridesharing and public transit options.

The extended duration closure is required for the contractor to demolish the existing on-ramp and build a new, significantly longer freeway on-ramp that, when complete, will have nearly 300 percent greater capacity than the current freeway ramp.  The new ramp will be 3,129 feet long compared with the current ramp at 824 feet, and is expected to allow far more vehicles to queue on the ramp rather than Wilshire and Sepulveda Boulevards. The ramp will be opened to be public as soon as it is complete.

The on-ramp averages 8,000 vehicles per day, according to the California Department of Transportation (Caltrans).

Detours

• Southbound Sepulveda Boulevard to Westbound Santa Monica Boulevard to Northbound I-405.
• Alternate Route: Southbound Sepulveda Boulevard to Westbound Pico to Northbound Cotner Avenue to northbound I-405.
• Night-time Route: Federal Avenue to Santa Monica Boulevard to Northbound on-ramp. Westwood Boulevard to Santa Monica Boulevard to Northbound on-ramp.

The Northbound Santa Monica on-ramp will be open in its final configuration prior to the start of the Wilshire ramp closure to handle the extra traffic resulting from the detour route.  The Santa Monica on-ramp currently has one lane, but after August 20 it will open with three lanes at the Santa Monica entrance that eventually merge into one lane at the freeway entrance.

The project team will deploy traffic control officers to key locations in the morning and afternoon peak period, and traffic control strike teams will patrol and monitor the area. Portable message signs will be used to advise motorists of the closure in advance.

The project team will work with the Los Angeles Department of Transportation to optimize the timing of traffic signals to help facilitate the movement of vehicles through intersections. The project team also will modify ramp meters at nearby on-ramps to help motorists more easily access the northbound I-405.

There are currently 27 on- and off-ramps that required realignment throughout the 10-mile project area.  At the Wilshire Interchange, Metro’s contractor has completed rebuilding three ramps so far.  Following the 90-day closure of the eastbound Wilshire on-ramp, the contractor will not require any additional extended duration closures in order to complete remaining ramps.  Intermittent night-time closures will still be required until all work is complete. The contractor developed alternate work plans and performed major construction activities at the interchange during night-time hours. The southbound ramps are being improved and modified and do not require complete rebuilding.  Other anticipated ramp closures at Olympic and Santa Monica also will not be required.

Once built, the reconstructed Wilshire Ramp interchanges will produce some of the I-405 project’s greatest local traffic improvements.  By building new, seismically updated and higher capacity ramps, the project will reduce the vehicular conflicts between Wilshire Boulevard and the I-405. This should reduce backup at other north/south streets, and bring capacity to meet expected vehicle demands in 2031.

Motorist safety will also be improved with the new interchange.  The existing off-ramp/on-ramp configuration presents a dangerous weave situation at two regionally important intersections: the Westbound Wilshire Boulevard on-ramp to the southbound I-405, and the Southbound I-405 off-ramp to eastbound Wilshire Boulevard.  At both these locations, drivers struggle to reach a through-freeway lane or change lanes to reach the off-ramp exit within a very short distance. New flyover ramps at these locations will be built to physically separate vehicles and eliminate these conflicts.

For additional project information or to obtain detour maps, visit www.metro.net/405.  Follow the project on social media at www.facebook.com/405project and http://twitter.com/I_405. For real-time traffic conditions, visit Caltrans web site at http://quickmap.dot.ca.gov.