Flagstaff Road is an arterial road in the southern suburbs of Adelaide in South Australia, Australia. It is one of the roads that carries commuter traffic between the city on the coastal plain and residential suburbs in the Adelaide Hills. The section with three lanes was upgraded to this standard in the 1980s to address increasing traffic due to expanding suburbs such as Flagstaff Hill and Aberfoyle Park. The overhead lane direction indicators were upgraded from green arrows to white ones using newer technology in 2013