As you may know, there's a bit of a tussle over whether to run East Link light rail trains on or beneath the surface of downtown Bellevue. And the tussle has revealed this whammy: light rail trains would not have signal priority in downtown Bellevue, meaning they could end up waiting, like glorified buses, at seven red lights while single-occupancy vehicles do their thing. Which is probably not what voters envisioned when they cast their ballots for light rail. I talked to East Link project manager Don Billen to get a little more info on this curious decision.
Because the trains are running on the surface, he said, their speed is already limited. "You need to operate at the same speed as surface traffic...even if you give them full priority, it's still going to be a relatively small amount of speed improvement." Billen said ST simulation models showed that "for average travel times through downtown Bellevue [the surface route without signal priority] adds 2-3 minutes, as compared to being elevated."
But what would be the consequence of giving the trains signal priority? Billen notes that the trains will run North/South while most of the downtown Bellevue traffic runs East/West, so "more than likely you would worsen congestion." Would it add more than 2-3 minutes to the average car commute? How many commuters would see their trips lengthened? "We have not quantitatively analyzed it," he said.