Oklahoma State Highway 270 1979, US-270 ran through Oklahoma City on surface streets. It left the city and ran through Choctaw concurrent with US-62. US-270 split away from US-62 in Harrah, and continued on to Shawnee on what is now SH-270. On March 5, 1979, US-270 was rerouted to run concurrent with Interstate 40 from south of Calumet in Canadian County through the Oklahoma City metro, exiting the Interstate onto a surface alignment in Shawnee. Presumably, SH-270 was commissioned the same date. The realignment of US-270, with SH-270 on the old alignment between Harrah and Shawnee, appears on the 1979 state map. SH-270 followed
Oklahoma State Highway 18 Oklahoma State Highway 18 State Highway 18, abbreviated as SH-18 or OK-18, is a highway maintained by the U.S. state of Oklahoma. It was once one of the longest state highways in the Oklahoma road system, but now has a total length of . State Highway 18 was commissioned in August 1924 and, at one time, traveled from Dickson, Oklahoma to Shidler, Oklahoma at the Kansas border. Much of SH-18 has been replaced by US-177. The current Highway 18 begins in Shawnee, Oklahoma at an interchange with US-177/270 and SH-3W. The highway is known as Harrison Street through Shawnee. After