The business case is to upgrade the Prospect Highway between Reservoir Road at Prospect and 200 metres north of St Martins Crescent, Blacktown (approximately 3.6 kilometres). It aims to provide a four-lane divided road along this section to reduce congestion, support public transport and freight movements, improve safety and more.

The business case was accepted for Infrastructure Australia's assessment on 14 July 2020.

On 8 December 2020, the Prospect Highway Upgrade was added to the Infrastructure Priority List as a Priority Project.