Heading outback? Here’s how to share the road with road trains

Passing a road train is less about nerve than arithmetic. The longest combinations on Western Australian highways now stretch to 53.5 metres, roughly double a 27.5 metre truck, per the Government of Western Australia. They are predictable once you know what the driver needs from you.

How long is a road train?

A road train is a prime mover towing two or more trailers, and the longest ones you will meet run to 53.5 metres. Triple combinations of that length have been cleared to keep working Great Northern Highway between Wubin and Muchea, part of a set of productivity measures the state government has extended to 31 December 2026.

Operators on that trial need three years or more at the wheel of combinations that long. The same extension also lets 27.5 metre and 36.5 metre combinations hauling fuel, fertiliser, lime, milk and bulk perishables take up to 10 tonnes more per load. A 53.5 metre triple is about twice as long as a 27.5 metre truck, so the stretch of clear road you need to get past one roughly doubles too.

Those lengths are being built into the roadside infrastructure, which tells you how routine they have become. A new road train assembly area planned for Norseman, on the Eyre Highway, is being drawn up with 36 bays, each long enough to hold a 53.5 metre combination, Big Rigs reported in February 2026.

You will see plenty of them. Drive west and you can count more than a hundred road trains before you arrive, says the National Heavy Vehicle Regulator, so this is worth sorting out before you leave the city behind.

How much room do you need to overtake one?

Far more than you would take to pass a car. The regulator’s We All Need Space campaign asks light vehicle drivers to allow three to four times the space they would leave around a car, which in practice means a long, uninterrupted run of sealed road before you commit to anything.

Signal well before you move out, so the driver can read what you are about to do. Then get past briskly, staying inside the limit, and don’t sit level with the trailers while you think it over.

Pulling back in is the part people hurry. The regulator’s test is both headlights: until the pair of them show up in your mirror, the rear trailer is still alongside you.

Best for overtaking a road train is a long sealed straight with the road visible to the horizon, nothing coming the other way, and a driver who already knows you are there. Short of that, waiting costs you a few minutes at most.

Where should you not try to overtake?

Not on a crest, not in dust, and not while the truck is turning. Any vehicle over 7.5 metres long carrying a DO NOT OVERTAKE TURNING VEHICLE sign may use more than a single lane to get around a corner, and passing it mid-turn is out. The gap that opens as the cab swings away is not an invitation.

Oversize loads work differently again. The regulator puts them at 2.5 metres wide or more, wide enough to occupy over half the road. Go past one only when the escort vehicle waves you through, and never overtake the escort itself.

On unsealed roads, overtaking is close to off the table. A road train on gravel drags a dust cloud behind it that hides its own rear trailers and whatever is coming the other way, and flings stones at your windscreen into the bargain. Sit well back, give the dust time to drop, and treat the whole stretch as a place to be patient. It is one of the things that catches people out on remote and unsealed roads.

How do you let a road train overtake you?

Hold a steady speed, keep left, and resist the urge to accelerate. The regulator’s advice to anyone being overtaken by a truck is to stay at whatever speed you were already doing and not push past the limit, because a road train that commits to a pass and then runs out of clear bitumen has nowhere to go.

Where you place yourself matters because of blind spots, the areas a driver cannot see from the cab or in the mirrors. The campaign counts four of them: just ahead of the cab, alongside the driver’s door, behind the last trailer, and down the passenger flank, which can swallow a car across as much as three lanes’ width for the full length of the vehicle.

Tucking in behind is the worst habit of the lot. Leave a gap of two seconds or more, stretched out further at night or in poor weather. A loaded truck also needs considerably more road to pull up than your car does, which is the other half of the reason that gap exists.

How do truck drivers use UHF radio?

They listen to Channel 40, and so should you. The regulator’s caravan etiquette advice points travellers to Channel 40 both for flagging that you are about to pass and for picking up what a driver ahead intends to do. Avida RV’s rundown of UHF channels calls it the main highway channel for truck and road train drivers, and says a call-up lets a driver with room to spare ease across to the left edge of their lane so you can see past.

Stay off 31 through 38. Avida RV flags those as repeater inputs rather than somewhere to hold a car-to-car chat.

Courtesy off the road counts as well. Truck bays at rest areas should be left for the drivers who need them, the regulator asks, because heavy vehicle drivers have to log their hours of work and rest by law. Plan your overnight stops around caravan parks or the caravan bays at larger service centres instead.

Much of the nervousness around trucks is really a knowledge gap. Of 1,000 drivers surveyed nationally and reported in December 2023, 51 per cent said heavy vehicles make them anxious or nervous, while just 32 per cent rated their own grasp of the rules as very good. The regulator’s chief executive, Sal Petroccitto, has made the point that a truck driver’s workplace is the road itself, and deserves the respect any workplace does.

None of this asks much of you. A bigger following gap, more patience at the overtaking line, a UHF radio switched to the road channel, and a willingness to sit behind a dust cloud for ten minutes rather than guess what is inside it. Do those four things and road trains stop being the part of the trip you dread.