Click above for a larger view. The second page of the letter is posted after the jump.

This isn’t the easiest issue to get our brains wrapped around — nothing involving transportation funding ever is. But this post involves good news for the Westside Subway Extension, with a letter from Federal Transit Administration chief Peter Rogoff to Rep. Henry Waxman reaffirming his agency’s desire to see the subway project planned all at once instead of in three segments.

In May, in a letter to Rogoff, Waxman had requested the FTA evaluate the subway project as one big project to Westwood.

Why does that matter? Because a project evaluated and planned all at once can possibly be built all at once, should the funding materialize via the 30/10 Initiative. And the subway looks a lot better from a ridership point-of-view when looked at in its entirety to Westwood.

Let’s back up and explain.

Metro is in the midst of working on the environmental studies required for the Downtown Regional Connector and Westside Extension. At the same time, the agency is also applying for federal New Starts funds to help pay for the projects.

The idea is that some of the money to build the projects will come from the Measure R sales tax increase approved by voters in 2008 and the rest will come from the Federal Transit Administration, which oversees New Starts — the program that helps pay for large local transit projects.

Click above for a larger view.

Under Metro’s current long-range plan, the subway would be built in three segments — to Fairfax by 2019, Century City by 2026 and Westwood by 2036 — using Measure R and New Starts funding. Why so long? Measure R funds flow into county coffers over time and have to be distributed among a wide variety of transit and road projects.

However, Metro is trying to speed that up with the 30/10 Initiative, which proposes to use federal loans and other financing to get the subway to Westwood in the next decade. In order to do that, the agency needs: 1) to first secure New Starts funding; 2) receive permission from the FTA to plan the subway all at once, and; 3) get 30/10 approved by Congress.

In June, U.S. Transportation Secretary Ray LaHood wrote that he backed planning the subway all at once. The new letter from FTA chief Peter Rogoff reaffirms that, meaning that Metro can now literally draw up the engineering plans to get the Westside Extension all the way to Westwood.

The 30/10 Initiative is still an uphill battle, as it’s something new and novel and Congressional approval for anything is never easy. For now, at least, the pieces seem to be falling in place.