New McLaren Vale intersection ‘islands’ explained
Published on 08 January 2025
A new road safety upgrade at a busy McLaren Vale intersection was completed late last year to help save lives.
Located at the intersection of Main Road, Johnston Road and McMurtrie Road, the upgrade has seen teardrop-shaped raised ‘islands’ installed on the side roads (Johnston and McMurtrie).
The islands make the intersection more obvious to drivers approaching from the side roads, and reduce the risk of drivers failing to stop (because they’re now forced to veer left on approach).
But what else should you keep in mind when navigating the newly upgraded intersection? Check out our handy guide below.
When approaching the intersection from Johnston or McMurtrie Road
As with any intersection, you should slow down and prepare to stop your vehicle before giving way.
If you’re turning left, wait until it’s safe to do so and then proceed like you normally would.
What if I’m turning right from one of these side roads?
If you want to turn right from one of the side roads onto Main Road, it’s important you pull up to the intersection at 90 degrees.
If you try to cut the corner around the raised teardrop island, you won’t sufficiently be able to look over your shoulder to see vehicles travelling towards you from the left.
Yellow raised plastic bumps have been installed in front of the teardrop islands to discourage drivers from cutting the corner, and to ensure you can safely check left and right before proceeding. Trucks can still safely drive over these humps because their turn path is wider than a normal car.
What if there’s a car waiting at the opposite side road and we both want to turn right?
If two cars pull up to the intersection and Johnston Road and McMurtrie Road and they both want to turn right, the car that got to the intersection first has right of way. Wait until they’ve turned right before you do.
What if I’m approaching the intersection from Main Road?
You have right of way, but as with any intersection, approach with caution.
Why has this been installed?
The upgrade is one of 21 being installed across the McLaren Vale region as part of a $4.2 million state government election commitment with the support of Leon Bignell, Member for Mawson.
An additional $737,500 was received from the federal government’s Black Spot program, with project delivery led by the City of Onkaparinga
The upgrades range from simple treatments (give way signs on yellow backboards), right up to high-tech flashing warning signs, teardrop islands and a roundabout.
The teardrop islands and roundabout – currently under construction at the intersection of Chalk Hill Road, Olivers Road and Field Street – are the final and most significant upgrades because these intersections have a higher level of crash trauma.
Why didn’t you install a roundabout at the Main Road, Johnston Road and McMurtrie Road intersection instead?
Civil upgrades such as roundabouts are very expensive and often involve land acquisitions, so they’re not something that can be easily or quickly installed everywhere.
A 2021 council intersection audit identified which of the 21 intersections have the highest risk and history of crashes, so the proposed upgrades and funding could be allocated accordingly.
Why didn’t you just use stop signs at this intersection instead?
The council doesn’t have the authority to replace give way signs with stop signs – these standards are set by the Department for Infrastructure and Transport.
Stop sign placement is governed by how far you can see down the road. A stop sign will be used when there’s not enough distance down the road for you to be sure there’s no traffic coming. Stop signs are also used sparingly so their effectiveness isn’t diluted – they’re reserved only for intersections where sight distance is a major factor.
In this intersection’s case, simply replacing the signs may not have had any impact on a distracted driver or someone unfamiliar with the area.
For example, the intersection of Chalk Hill Road, Olivers Road and Field Street (where the roundabout is being built) previously had stop signs, and it still had by far the highest reported crash rate of any of the 21 intersections being upgraded.
The McLaren Vale district was surveyed in the nineteenth century, and it produced a predominantly grid-based network of roads and land parcels.
While this road network pattern helps us to get around more easily, the resulting four-way junctions do increase the potential for crashes.
Using teardrop islands to make the Main Road, Johnston Road and McMurtrie Road intersection more obvious and to stagger drivers’ approaches was identified as the most appropriate upgrade in this case.