Page "Graham Farmer Freeway" Paragraph 2

The freeway incorporates Western Australia's only freeway tunnel, the Northbridge Tunnel.

The tunnel has two traffic lanes and an emergency stopping lane in each direction, with an escape passageway between the carriageways.

The tunnel is colloquially known as the " Polly Pipe ", a reference not only to the freeway's namesake, but also to the colloquialism " Poly Pipe " in reference to plastic pipes ( commonly made from polyethylene or polyvinyl chloride materials ) used in reticulation and plumbing.

Both tunnel portals feature public art installations.

At the western end, there is a pictorial history of Northbridge, and at the eastern end, the Aboriginal artist Ron Corbett created images based on indigenous artwork.

The transportation of dangerous goods and explosives through the freeway tunnel is prohibited.