The proposal is to upgrade and widen the Brookton Highway between Armadale and Brookton. At present the road has a safety problem because the road and its gravel verges are narrow, there are sharp corners and the surface is hilly and rough.

A portion of the Highway passes through an area of State Forest which was identified as potentially valuable for conservation by the Environmental Protection Authority in its System 6 'Red Book' report of 1983 (recommendation C37). The values of this area include: the natural vegetation of the Darling Range, particularly the extensive forest areas of jarrah, marri and wandoo which is accessible to travellers, the many wildflowers to be seen in the understoreys, and the values for scientific study.

Sections of the Brookton Highway will be upgraded by widening of the sealed road area and the verges and drains. Curves and hills will also be smoothed. Four areas within the State Forest section will be realigned.