Which way on light rail?

Who deserves a light-rail line more, the people of Azusa or the people of Santa Monica? Which line makes more sense, one that would serve the future needs of fast-growing communities to the east, or the current needs of the traffic-choked Westside?

The Metropolitan Transportation Authority is faced with the unenviable task of answering these questions on Thursday, when its board is slated to vote on a long-range transportation plan -- a blueprint for the future of the L.A. County public transit system. Most of it is noncontroversial, but one item in particular has devolved into an ugly regional tug of war between cities to the east that feel they’ve long been ignored by L.A. transit planners and parts of West L.A. that have among the worst traffic problems in the country.

The dispute centers on a proposed spur of the Gold Line, which runs from Union Station to east Pasadena. San Gabriel Valley politicians are lobbying fiercely for an 11.4-mile extension to Azusa, a project that isn’t currently slated for funding under the MTA’s 25-year plan. They believe that if the MTA will set aside $80 million, they can drum up the additional $320 million needed to build the line from the federal government. But therein lies a serious problem.

There is only so much federal transportation money to go around. The fear is that if the Gold Line extension gets on the fast track, another project would fall off -- and the most likely victim is a planned extension of the Exposition Line. Construction on the first phase of the line from downtown L.A. to Culver City started in August; the second phase, which would go through Santa Monica, is slated for funding under the MTA’s draft long-range plan. But if the Gold Line extension gets federal money, there may be none left over for Expo.

If one looks solely at ridership, this isn’t a tough decision. Once both phases of the Expo Line are completed, they’re expected to attract 62,000 riders a day. The Gold Line, which currently has about 24,000 riders a day, would get an estimated 10,000 more with the extension. And yet it would pass through burgeoning population centers where officials are planning high-density projects near light-rail stations, which would encourage future use. And if the line is eventually extended to Ontario International Airport as planned, it would help spread air traffic away from Los Angeles International Airport, which is bursting at the seams.

The best decision for the MTA board, then, would probably be to put off making a decision. L.A. doesn’t need one or the other of these projects, it needs both. There is ample room for a compromise, because a measure expected to appear on the November ballot would ask county voters to approve a half-cent sales tax increase to fund public transit. If the measure passes, there will be enough money to build both light-rail lines. The long-range plan should be redrawn with this in mind; meanwhile, local officials should be working harder to secure federal funds for both projects.