What happened to the colored US routes?
AZ, MS, RI, and WA, and reportedly CT, DC, SD, and UT, formerly used a system based on direction, with AZ briefly using them again for its Phoenix loop highways. KS used green and white markers for US 56. NE and WI used yellow shields on City routes (analogous to business routes), and AK, GA, MD, SD, and OH use green on some or all current US and state business routes. ID substitutes brown for black on its scenic-designated routes, a color scheme mimicked on many historic alignments of formerly numbered routes, usually US routes. AL and GA use colors on certain corridors. But the most interesting (and most recently removed) case has been FL. Each route got a color, and 2 routes of the same color never intersected until US-192 was extended west to US-27 (both green). Eventually AASHTO made FL stop using them if they were funded with federal monies. Many colored signs are still up, most now having been manufactured by FDOT. More information: AZ: http://www.arizonaroads.com/wrong/wrong1.h
