After intersecting Bishop Boulevard, SR 270 turns due east onto the Pullman–Moscow Highway, which follows Paradise Creek along the south side of the university campus.

[8] After passing the university arboretum and a road leading to Pullman–Moscow Regional Airport, SR 270 turns northeast and leaves Pullman city limits.

SR 270 then dips southeasterly after intersecting the airport access road again and rejoins the freight railroad before it reaches the Idaho state line at the western city limits of Moscow.

[14] A parallel railroad was also built to the south by the Northern Pacific Railway in 1887, along with an unpaved highway running between the two towns near Paradise Creek.

[15][16] The original road between Pullman and Moscow was impassible during inclement weather for automobiles, leading to calls for a permanent highway.

[24][25][26] A plan was announced by WSDOT in 2001, prompted by a fatal crash that killed three WSU students, with a 60-foot (18 m) median between directions of traffic.

[29] The original design of a 60-foot (18 m) center median, similar to a rural interstate highway, was revised due to right-of-way costs.