Metro on 75/372 Routing
A couple weeks ago, I asked for reactions to the possibility of altering King County Metro routes 75 and 372 to mirror the couplet path of routes 65/67 and 78 through the University of Washington campus.

New Metro Route 78
Jeff Switzer from the King County Department of Transportation got back to me within a couple days with a response from Metro planners, but I was headed off to vacation. So, here it is, posted belatedly:
Route performance is part of our ongoing monitoring since making so many changes this spring. Thanks for raising this question as part of the discussion on reviewing and improving bus service.
As we discussed the restructure, we worked to balance the need to provide transit service to the campus and maximize the access to UW Station. There are an estimated nearly 3,000 riders using Stevens Way stops on these routes today, and there continue to be pluses and minuses to going with a one-way couplet of having westbound service on Stevens Way and eastbound service on Pacific/Montlake.
Pluses:
More convenient access for riders transferring from Link to northbound service on Routes 75 and 372.
More convenient access to the UW Medical Center in one direction.
More convenient transfer from eastside bus routes to Routes 75 and 372
More frequent service from a single UW Station stop to destinations like University Village and Children's Hospital
Minuses:
Riders originating on the UW Campus trying to catch Routes 75 and 372 have to walk down to NE Pacific Street (there were 2,032 boardings at the four campus stops for routes 75 and 372 in Fall 2015)
Riders destined for places on the UW Campus coming from Routes 31 and 32 (these routes become Route 75 at NE Campus Pkwy) would need to walk up on to the UW Campus from NE Pacific St (there were 889 alightings at the four campus stops for Routes 31 and 32 in Fall 2015)
The travel time using NE Pacific Street and Montlake Blvd NE is slightly longer than traveling on Stevens Way, slowing riders who board at NE Campus Pkwy in the U. District or who are riding Routes 31/32-75 through the U. District.
The couplet service pattern is more confusing and more complex (the author notes this).
The bus stop northbound on Montlake Blvd would become much busier causing congestion on the sidewalk. Currently there are about eight trips per hour in the peak period. With Routes 75 and 372 also serving this stop, the number of trips would rise to over 20 per hour.
Buses block general purpose traffic when serving the in-lane bus stop northbound on Montlake Boulevard. An increase in bus volumes would cause more frequent blockages.
Adding more buses to the northbound Montlake Blvd stop could require shifting the stop farther north to accommodate more bus curb access/storage. Doing so would increase walk distance for intermodal transfers.
At the moment, Metro sees the minuses as outweighing the pluses as there are more riders on Routes 75 and 372 coming from destinations on the UW Campus than there are riders transferring from Link. In other words, more people might have to walk farther under a revised couplet scenario than the number of people who would walk a shorter distance to transfer from Link to Routes 75 and 372.
We will continue to monitor ridership and boardings at the Stevens Way/Rainier Vista stop on these routes to better understand how many riders would benefit from moving the routes closer to UW Station.