When first posted in as such in 1964, SR 270 began at Jct US 195 in downtown Pullman and headed east to the Washington-Idaho state line, where SR 270 ended and Idaho SR 8 begins. In the mid 1970s, a new alignment of US 195 was built, bypassing Pullman to the SW. SR 270 was extended west along former US 195 to join US 195 west of town. SR 27 was extended south along former US 195 to join US 195 south of town. SR 270 and SR 27 share the same roadway for a few blocks in downtown. Today, SR 270 is 9.89 miles long.
Before 1964, SR 270 had been part of the Colfax-Pullman branch of PSH 3.
In the 1970s, there was a proposal to reroute SR 270 around the SE side of Pullman. In conjunction with the US 195 SW Pullman bypass and a proposed SR 276 bypass of the north side of Pullman, the SR 270 bypass would have completed a ring road around Pullman.
If I were the state highway numbering czar, I would change SR 270 to some other number. I think that SR 270, although relatively short, should have a one or two digit route number. As noted above, under the old state highway numbering system SR 270 was a primary state highway, one of the many branches of PSH 3. The Washington SR 270/Idaho SR 8 corridor links Pullman with Moscow, each home to a state university and the largest city within their county. My vote is to renumber Washington SR 270 as Washington SR 8. This would give a single number to the route from Jct US 195 near Pullman to Jct US 95 in Moscow. Oh, but there already is an SR 8 in Washington, from Jct US 12 at Elma to Jct US 101 at Mud Bay west of Olympia! I would renumber the existing SR 8 something else. My vote is for Spur US 12.
Until US 12 was extended into Washington State in late 1967, one could follow a single route number from Olympia to Aberdeen, US 410. Granted, US 101 overlapped US 410 for about a half dozen miles on the west side of the Olympia area. Today, one must follow three different route numbers on the direct highway from Olympia to Aberdeen. Northbound US 101 from I-5 to Shelton exits from itself at Jct SR 8, with the lefthand thru lanes continuing as SR 8. Eastbound US 12 exits from itself at Elma, with the thru lanes continuing as SR 8. Some people don't realize that they leave US 12 and think that US 12 is the route number that continues towards Olympia. Why didn't US 12 just follow the whole route of former US 410 across the state, rather than departing from former US 410 between Elma and the Naches area? One reason is that US 12 crosses White Pass, elevation 4500 feet and opened in winter. The former route of US 410, now SR 410, across the Cascades, uses Chinook Pass, elevation 5,430 and closed in winter.
Yes, US 12 Spur would be the longest spur on the US numbered highway system, but I see limited alternatives. A three digit US route number is out since Elma to Olympia is totally in one state and less than 300 miles long. Renumbering all of former US 410 from Elma to the Naches area as Alt US 12 is in theory an option but I think that the public would rather keep the Chinook Pass Highway numbered as 410, the number that it has had since 1926. Also WSDOT probably doesn't want to add the Alt US 12 designation to I-5 from Olympia to Tacoma. If the Olympia- Aberdeen corridor were to be upgraded to full freeway, the route could become I-88. Such an upgrade won't happen soon, if ever. Renumbering present SR 8 to something else and changing SR 270 to SR 8 may never happen, but who knows.?
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