Motorist's route finder (7)
(Other definitions for road map that I've seen before include "Some town-planning" , "Political plan" , "Driver's chart showing routes" , "Document detailing route to an end" , "superseded by satnav?" .)
(Other definitions for roadmap that I've seen before include "Plan for solving international problem?" , "Street plan" , "Driver's navigation aid" , "Document charting the way forward" , "Travel guide" .)