In last Friday’s B7 writeup, a post-RSS addendum to the story stated that although the cost of the actual B2M and B7R segments differed by $40m, the choice of B7R incurred an additional $100m of costs in the C (Downtown Bellevue) Segment. Some commenters asked reasonable questions about the data, so I’ve reproduced below table 2-2 from the East Link Supplemental EIS, which is a cost matrix of the various B and C segment choices.
As you can see, the total difference is $140m-$160m. Furthermore, B7R incurs an additional $9m of costs [Table 2] in the C segment over vanilla B7 in table above, making the total gap between B2M and B7R at least $150m. There are certainly both drawbacks and benefits to a B7R alignment, but the large cost difference is probably a significant argument for Sound Transit’s preference, B2M.