> And catch the 10 years to build a viaduct. Did we not go to the moon in that time?

Counting from when you decide to do it and start raising money, yes, 10 years is very possible. Especially with the current transportation funding crunch - get in line.

When SacRT decided to do the grade sep at Watt Ave. on the Gold Line, it took about 5 years to get the money tied down, a couple of years to do environmental and engineering work (somewhat special engineering because of the "through girder" type of concrete structure that minimizes the climb from the station that was kind of close to Watt, plus arranging the shoofly), and almost 3 years to build (OK, they did have to fire the original contractor and re-bid; should have taken about 2 years). Using all my fingers, that looks like 10 years, close enough. And the crossover west of the bridge, built to use with the shoofly, is still a bad spot that trains have to slow down for; the original contractor built it, and it feels like some misalignment is still present.

If San Rafael and SMART get started now, they might, possibly, just scare up the money for a grade sep in 10 years; CTC pretty much eliminated funding for new projects recently. BTW, I suspect it would work better to run the road over the rail rather than the other way, but that's something for future discussion if it ever looks like there's money.