The temporary fencing will be erected in the next couple of weeks, which RAA road-safety expert Charles Mountain said would be a “real test” to see if this will be sufficient to deter rock-throwers.

Permanent fences are expected to be installed later this year.

It seems an increased police presence with dog squads and helicopters has not stopped offenders, as 3 new rock-throwing incidents were reported just this week.

The number of motorists who’ve had an object hurled at their vehicle from the Southern Expressway bridges has risen to more than 40 since the start of this year.

Loose rocks have already been covered with mesh near the Honeypot Rd Bridge. All rock embankments along the expressway will eventually be covered and fenced off from the public.

CCTV cameras along the expressway will also be upgraded, with the camera at Flaxmill and Beach Rd Bridges already improved.

“It’s a concern for people travelling here, not only in terms of damage to their vehicles but potential injury to themselves and their passengers,” Mr Mountain says.

Despite increased security, road-users are still encouraged to report any suspicious behaviour in the area to police as soon as possible.

What should you do if an object’s thrown at your vehicle along the expressway?

RAA recommends you pull over as soon as it’s safe to do so before you dial 000. In the meantime, drive safely and we’ll keep you updated on any progress as we hear about it.