SR 255 was created around 1969 as part of a proposed northern bypass of Huntsville. The original route ran from Redstone Arsenal Gate 9 to US 72 as limited access highway with exits for U.S. Route 72 Alternate/SR 20 (now Interstate 565), Old Madison Pike, and ending at US 72, with plans to extend north. The interchange with SR 20 was intended only to provide access to the Arsenal's Gate 9 and accordingly had an incomplete set of ramps; going southbound on 255 there was no direct access to 20, and from 20 it was only possible to enter 255 going southbound. SR 255 only appeared on maps and was unsigned, and was better known as Rideout Road. The road continues southward past Gate 9 into Redstone Arsenal and actually has an additional interchange at the Toftoy Thruway, but this is not considered part of the state route.