National Highway is a major route in WA, directly linking the capital city of Perth with the mining and goldfield regions in the eastern part of the state, such as Kalgoorlie and Norseman, it also connects to National Highway 1, the Eyre Highway, which is the major link, via the Nullarbor Plain between the east and west coasts of Australia.
Outside of Perth, the route is bitumen paved single carriageway roadway. Some overtaking lanes exist along the route between Coolgardie and Perth's outer suburbs. Inside the metropolitan area, the route varies from multi-lane arterial road to expressway standard.
The highway generally runs parallel with the Mundaring to Kalgoorlie water pipeline, which pipes drinking water drawn from Mundaring Weir near Perth to Kalgoorlie.
This page concentrates on the former alignment between Perth and Mundaring
AD sign gantry approaching Tonkin Hwy (SR4) interchange at Redcliffe, March 2019. Click or tap here for a photo of this location by Paul Rands from April 2016. Click or tap here for a photo of this location by Paul Rands from December 2012.
Image © Paul Rands
AD signage approaching the Tonkin Highway (SR4) interchange at Ascot, April 2016. Click or tap here for a photo of this location by Paul Rands from December 2007.
Image © Paul Rands
ID sign facing eastbound traffic at the Tonkin Hwy (SR4) interchange in Ascot, April 2016. Click or tap here for a photo of this location by Paul Rands from December 2007.
Image © Paul Rands