mandatory keep left obstacle detour road sign, united kingdom uk traffic safety barrier signage on pole post, large blue

accident arrow attention barricade barrier block blocked blue caution closed closeup concept danger detailed detour diagonal drive driving equipment europe guide hand highway icon info isolated keep kingdom lane large left mandatory marking metal obstacle panel pattern pole post red regulatory reroute road roadside roadsign roadworks round route safety shield sign signage signal signalling signpost site street stripe striped symbol town traffic united urban vertical warning way white works zone