Primary and secondary state highway system (1937 to 1964)

[Bruce]

Came across an interesting proposal to renumber the primary/secondary highways (aka the former number-and-suffix system) from 1957, which would have turned a few dozen secondary branches into primary routes. Highway 51 to Monroe! Highway 40 to Westport! Highway 56 to Moses Lake!

[NE2]

Is this from Washington's version of CH&PW?

[Bruce]

It's from the March 1957 edition of Washington Highway News (found here at the WSDOT Library Digital Collections).