Since 1994, roads along the ORRS have been upgraded in stages to provide a smoother route to travel across the island.

Roads and interchanges along the ORRS are constantly being upgraded to cater to the ever increasing traffic demand.

The series of roads passes through the areas of Queenstown, Bukit Timah, Central Catchment Nature Reserve, Bishan, Toa Payoh, Geylang and Tampines.

The route of the ORRS forms a semi-circle shape, connecting several expressways and major arterial roads.

Travelling from west to east in a clockwise direction, the route begins at Queenstown with a connection to the Ayer Rajah Expressway.