LOS ANGELES --
Metro's purple line subway could be extended if Los Angeles Mayor Antonio Villaraigosa has his way.The mayor is expected to ask the MTA board Thursday to allow private investors to pay for the extension which would run from Wilshire Boulevard to the city of Santa Monica. Villaraigosa said the "Subway to the Sea" project will help ease congestion on Wilshire. However, extending the subway could cost at least $5 billion and take 10 years to build.