With the exception of Worthing itself, it is one of the worst quality sections of the A27 corridor between Portsmouth and Brighton. Although a single carriageway bypass was built in the 1970s, this was not sufficient for a trunk route along the South Coast, and plans were made to create a proper dualled and grade separated bypass around 1996 - most obviously seen by the unfinished junction with the A27 and A284 at Crossbush, south of the town centre. These were formally cancelled in 2003, but campaigning for the bypass, most notably by local MP Nick Herbert, continues.
In the meantime, several projects have been taken up to extend the life of the existing A27, which wasn't designed with such heavy traffic flows in mind. The single carriageway layout means that these almost inevitably create long delays.