​​​​​​​​​​​​Yellow box intersection trials

The problem

Vehicles stopping or queuing across an intersection can cause gridlock on the road network, not to mention the frustration caused to other drivers who are unnecessarily blocked and cannot move through an intersection. 

The solution

Yellow boxes are successfully used around the world to discourage drivers from stopping within intersections and blocking other vehicle movements. 

A yellow box is painted on the road to show the extent of an intersection and indicate an area where drivers should not stop.  You may only enter a yellow box intersection when your exit is clear and there is enough space on the other side of the intersection for your vehicle to clear the box completely without stopping.

Drivers who are turning right can stop at an intersection if their turn is prevented by oncoming traffic until it is safe for the turn to be completed.  Drivers must not simply follow the car in front through a yellow box as they must not enter the yellow marked area unless your exit from the intersection is clear. 

By discouraging intersection blocking, yellow boxes can help to improve traffic flow not just at the intersection but right through a road corridor.

When and where

Following a successful trial, we are rolling out yellow box line markings to a further 12 intersections on the Perth metropolitan road network:

    • James Street and Johnson Street, Guildford
    • James Street and Meadow Street, Guildford
    • Ellen Stirling Boulevard and Scarborough Beach Road, Innaloo
    • West Coast Highway and Manning Street, Scarborough
    • Stephenson Avenue and Scarborough Beach Road, Osborne Park
    • Cedric Street and Ellen Stirling Boulevard, Innaloo
    • Stirling Highway and Bay View Terrace, Claremont
    • Stirling Highway and Leura Avenue, Claremont
    • Albany Highway and Liege Street, Cannington
    • Orrong Road and Wright Street, Carlisle
    • Canning Highway and Ardross Street, Applecross
    • Canning Highway and Preston Point Road, East Fremantle

​Watch our video below to see how it's done. Remember, if there is a yellow box, no yellow box or even a chili crab - same rules apply.


The trial

In early 2016, two types of yellow box designs, using Singapore and UK markings, were implemented at the following locations (click on the images for a larger version)

The two types on trial were:

  • A large box with a single cross within a boxed intersection (Singapore markings)
  • A large box with hatching throughout the intersection (UK markings)

Through before and after analysis, the results showed that the Singapore style was the most effective overall to implement across the network as a traffic flow improvement measure.

The trial also confirmed that the yellow box markings had reduced the number times vehicles queued across the intersection. See the trial locations below.

Canning Highway and Kintail Road, Applecross


Queen Victoria Street and Tydeman Road, North Fremantle​


John Sanders Drive and Herdsman Parade, Glendalough​



Mitchell Freeway southbound off–ramp / Vincent Street / Leederville Parade, Leederville​



Last Updated: 10 July 2017