It is a common occurrence on Australia's regional roads: A truck driver, taking advantage of their elevated position, flicks their right indicator to signal to cars behind that it is safe to overtake.
It is a longstanding practice, especially in the far north and interior, where road trains travel hundreds of kilometres on open highways.
But this act of politeness is actually against the law and recent near-misses, where drivers have mistaken a turning truck for one saying it is safe to pass, have led WA's peak mining body to urge drivers to stop the practice.
Chamber of Minerals and Energy north-west officer Meghan Brouwer said mining companies were receiving an increasing number of reports of dangerous close calls.
"Trucks have been turning right into mine-site entrances only to have other vehicles attempt to overtake at the same time," Ms Brouwer said.
"This practice, while intended to be courteous, is actually dangerous and illegal."
Veteran WA truck driver and instructor Heather Jones echoed Ms Brouwer's message, arguing it was easy for misread signals to turn catastrophic.
"A few years ago there was a caravan and car travelling really slowly in the Pilbara, he put his indicator on and the truck behind him went out and passed him," Ms Jones said.
"But unfortunately the car [was actually] turning into a 24-hour parking bay."
Ms Jones has had her own near misses when people misinterpreted her turn signal.
"A few years ago I had a four-and-a-half metre wide load on my truck, and the pilot in front of me said, 'There's a cow on the road', so I put my right indicator on to move into the other lane," Ms Jones said.
"Next minute, there's fluff and dirt and everything is flying around — it was a lady in a car who thought I put my indicator on for her to go past me."
"People don't know it's illegal — the amount of drivers you mention this to, they have absolutely no idea."
Two-way radios the best solution
WA Road Safety Commissioner Adrian Warner said he understood people's attachment to the practice, but said the dangers it presented were clear.
He said two-way radios were a safer way for truck drivers and other road users to communicate.
"It's a convention people have got used to doing, and it's a reflection of courtesy and sharing the road, which we would usually promote — but it can be dangerous," Mr Warner said.
"I appreciate the courtesy of someone saying it's clear ahead, particularly if you've been stuck behind a heavy vehicle for a few kilometres.
"But it really is up to each driver who is sitting behind a vehicle — don't rely on interpreting a signal that could well be a turning right signal."
Ms Jones said communication and safety were key for all road users.
"The best thing - especially in regional areas - is just grab yourself a two way radio, go to channel 40 and talk to us."
