This post originally appeared on Orphan Road.

Decoding the pluses and minuses of the various SR-520 bridge replacement options is no easy task. Apparently several Seattle-based politicos have decided to oppose WSDOT’s preferred option, “A+” (option A is shown in the video above).

If I understand the argument correctly, A+ would offer 4 general-purpose lanes, 2 in each direction, plus one HOV lane in each direction (the current bridge has only 4 general purpose lanes). The Seattle coalition wants 4 GP lanes plus two transit-only lanes (no HOV). I guess their argument is two-fold: (a) HOV means more car traffic, and (b) transit-only lanes would be easier to convert to light rail at some point in the future.

My first reaction is that it’s crazy to not build HOV lanes. Giving people an incentive to carpool is important. It’s been said that most cars run at 25% capacity at rush hour (3 empty seats). Simply adding one person doubles that to 50%, resulting in twice as many people using the same number of cars. That’s huge.

Upon further reflection, though, I wonder how tolls will figure into this equation. Tolling will create its own incentive to carpool, and variable tolling can be used (if WSDOT has the stones) to manage demand so that traffic almost always runs smoothly in the GP lanes. If that’s the case, you could easily imagine it all working out.

Ultimately, I agree with Ben that the Montlake flyer stop is more important than any of this.