Wiktionary
red route
n. (context chiefly British English) A system of traffic management, marked by red lines along the edge of the road, where parking, loading or picking up passengers is restricted.
Wikipedia
Red route
__NOTOC__ The term red route has been separately adopted for two entirely different highway purposes within the United Kingdom.
Usage examples of "red route".
Navy was now calling Red Route One, and to listen for any external evidence of a new gadget that might enable the Soviets to run the ridge so boldly.