 Main Roads Western Australia monitors traffic volume across the state 's road network , including various locations along North West Coastal Highway . In the 2012 / 13 financial year , the recorded traffic volumes ranged from 13 @,@ 350 vehicles per day west of Geraldton – Mount Magnet Road down to 370 north of Minilya – Exmouth Road . The highest percentage of heavy vehicles was 45 @.@ 5 % , west of Karratha Road . Reports commissioned by the Royal Automobile Club of Western Australia ( RAC ) in 2006 and 2008 gave most of the highway a four @-@ star safety rating out of five , but with a significant proportion rated at a three @-@ star level . The overall highway network was generally rated as three @-@ star or four @-@ star , with around 10 % in 2006 and 5 % in 2008 receiving a two @-@ star rating . 
