Milepost 90 (B) on US-395 south. The B is because the state of Oregon maintains different internal highways along the state highway system. Some of the signed highways (like US-395) span multiple internal highways. In this case this is the second internal highway south from the Washington border that belongs only to US-395. The first (Umatilla-Stanfield #54) is marked as an A on mileposts. This is the second (B) stretch - Pendleton - John Day #28). This type of milepost has been showing up in Oregon in the last 10 years, but not on all highways. I have seen it on US-395 and OR-207.