While the proposed Westside subway extension is expected to provide substantial benefits to transit riders, the multibillion-dollar project -- contrary to one of its selling points -- will do little to relieve traffic congestion in West Los Angeles, a new environmental review shows.



Released Friday, the subway’s draft environmental impact report states that the project will give transit users more options and allow them to travel across town much faster than the municipal buses that serve the densely populated Wilshire corridor.



Transit officials estimate that a one-way subway trip from downtown Los Angeles to Westwood would take about 25 minutes, something that is now difficult to do in a car at rush hour. Buses make the trip in at least 50 minutes, a time that will only lengthen as Wilshire Boulevard and parallel thoroughfares become increasingly choked with traffic.



The report shows, however, that in 2035 the subway extension will only result in a tiny reduction in autombile use -- around 1% -- and that the San Diego Freeway, the Santa Monica Freeway and major streets along the line will remain heavily congested due to population growth.



“Remarks that transit relieves traffic congestion are common, but they are without a factual basis,” said Tom Rubin, a transportation consultant and former transit agency executive in Southern California. “The roads in Los Angeles are so far over capacity, it is difficult to get improvement from new transit projects.”



Traffic relief has been one of the goals of the light rail and subway projects planned and built by the Los Angeles County Metropolitan Transportation Authority. Elected officials and MTA board members, including Los Angeles Mayor Antonio Villaraigosa, have repeatedly said that the Westside subway extension as well as other proposed rail projects are needed to alleviate congestion and gridlock.



Though traffic congestion will remain a vexing problem, MTA officials say the Westside subway extension will provide a large incentive for motorists to break their automobile dependency because of shorter travel times and a longer route with stops at job centers, tourist attractions, cultural institutions and UCLA.



“We have shown that when we give the public new options, people get out of their cars,” said David Mieger, the project manager for the Westside extension. “The subway will be a good alternative to the automobile. Why would you continue to drive?”