New Zealanders have been flashing their hazard lights as an on-road thank you for decades. But where did the phenomenon come from? How widespread is it? And is it even legal? Naomii Seah investigates. 

One blazing hot day at the beginning of summer, my life changed forever. 

Here’s how it happened: my friend Maddy had very kindly offered me a ride into university. We were sitting side by side, air-con blasting to combat the summer humidity. All was well in the world when we pulled up into a long two-lane queue.  

“Oh no, I’m in the wrong lane,” said Maddy. She flicked her right indicator on and inched forward, doing the slightly apologetic I’ve-made-a-mistake-on-the-road dance. Miraculously, someone let us in. That’s when it happened. Maddy leaned forward, and pressed the hazard lights button on her dashboard, waving over her shoulder as she did so. 

“Wait, what are you doing?” I asked, wide-eyed. I’d never seen anyone use their hazard lights before, let alone casually in the middle of the road. Wasn’t that illegal? 

“It’s something you use when you recognise you’ve been a bit of a hazard,” Maddy laughs. She explained that it’s a thank you to other road-users when they’ve done something nice, like letting you into traffic. I’d never seen it before. What an elegant solution, I thought. The hazard flash was visible, quick and clear. At that point I wasn’t yet fully convinced, but I was well on the way to being a hazard-light convert. 

The unofficial road code

I knew what hazard lights were for in theory, but I’d never had to use them. At least, not in the way you’re meant to use hazard lights. The NZTA says you’re only supposed to use your hazard lights when your vehicle becomes hazardous to other road users. Examples given include changing a tyre by the road, or being towed. According to drivingtests.co.nz – a website that yanked me violently back to my teen days – hazard lights shouldn’t be used while driving, or when parked in a dodgy position. 

So… does that mean using your hazards as a thank you is illegal? Well, there’s no law specifically preventing it, so it seems like using your hazards on the road may be akin to flashing your headlights to warn others of police presence – allowed, but frowned upon. Well, frowned upon by the relevant authorities, anyway. 

After I’d seen Maddy flashing her hazards that fateful summer day, I adopted it. The next time someone let me into traffic, I hovered over that hazard button on my dashboard for a split second before giving it a double tap. I experienced a brief moment of panic – what if, like me not too long ago, the driver didn’t understand what the signal meant? 

But according to a BP survey conducted in 2019, almost half of Aucklanders used their hazard lights as an on-road thank you. This was colloquially confirmed by my friends, even the non-jafas, most of whom told me it was common knowledge and gently ribbed me for being a dunce. 

“It’s something I would see my parents doing on my way into school,” said Maddy in a follow-up call. It had been months since she’d introduced me to the hazard flash, and I couldn’t stop thinking about it. 

“It’s a nice way to say a quick thanks and maybe also apologise if you did something that’s not technically in the road rules.” 

It took Maddy a while to start using the hazard flash herself. She said it was only after she got comfortable on the road, and learned the “etiquette that’s not theory based, more so learnt from practical application” that she started using her hazards.  

I’ll confess that I didn’t “get” the hazard lights phenomenon immediately. But one day, feeling generous after a long day at work, I slowed to let a harried-looking woman in a black Suzuki in front of me. We made eye contact through her smudged passenger window, and I recognised myself in the dead look in her eyes, and the messy bun and eye bag combo she was sporting. I gave her a smile. She then promptly sped off in front of me, without so much as a hazard flash of acknowledgement. All my warm feelings towards her promptly dissipated. Pardon my French, but what the fuck? I fumed all the way home. 

It got me thinking. Just how did the hazard flash become a thank you button? How long had it been used that way? Where did it come from? And was it really such a ubiquitous signal? Did that woman snub me, or was she just uninitiated? 

The origins of the hazard flash 

Like any good researcher, I started my search for the origin of the hazard flash on the foremost source for social discourse anywhere in the world: Reddit. There, New Zealanders shared their experiences of the hazard flash. Commenters said they’d seen the practice in New Zealand as far back as 30 years ago, but some thought it had become more common in recent years. 

The leading theory was that the hazard flash is an imported phenomenon, with users citing many countries of origin, including the UK, South Africa and Japan. A little more googling showed Japan as the most likely country of origin – there, the signal is so common it’s known as the “thank you hazard”. According to this Japanese language source, the signal originated in Japan during the mid-80s. 

But the mystery is not so easily solved. What about the users who claimed to have seen it in New Zealand since that exact time? What about Maddy, who’d told me she’d picked it up off her dad Jon, who in turn told me he picked it up from his “old man” in the UK? That meant the hazard flash was around in England since the early 80s. 

Another running theory on the Reddit thread was that the hazard flash originated in our trucking communities. I picked up the phone. There were a few false starts – mostly stony silences from people wondering if my question about hazard lights was a prank – but finally, I got hold of the owner of an Auckland-based trucking company. According to its website, the company was founded in 1921, and is family owned and operated to this day. Surely they could provide some answers. 

“I’ve been in the [trucking] business for 35 years,” the owner said, “since I left school.” Aha, I thought. This was promising. I pressed ahead, and asked him where he picked up the hazard flash. 

“I think it’s just bloody one of those things that you know,” he said. “It’s like [knowing] when you need to go to the toilet. Doesn’t take any more than bloody half a second to push a button on your dash or whatever; give someone a wave or a wink, does it?” He denied that hazard flashing originated in the trucking community, saying it was common as a thank you from other road users, mostly passenger cars. 

He then reminisced about the “good old days” when a hand out the window was the agreed upon thank you signal, telling me he’s only seen the hazard flash become common in recent years. 

“Now, of course, we live in this cocoon,” he said, referring to modern air-conditioning. In his opinion, that’s why the out-the-window hand wave has been replaced with the hazard flash – people don’t want to let their air-conditioned air out. However, in his estimation, the hazard flash has been around “for a good 10 years or more”. 

He said he sees a lot of “young people” using their hazard lights in that way, as well as a lot of “bloody immigrants”. It’s at this point that I wondered if I should tell him I’m not Caucasian. I gave him the benefit of the doubt. Maybe the swearing is a habit – I’ve certainly sworn at inopportune moments. Nevertheless, I quickly ended our call, no closer to discovering the origins of the hazard flash.

The spontaneous simultaneous origin theory 

After a few more days of futile attempts to trace the hazard flash back to a point of origin, it suddenly dawned on me that I may have been searching for something that doesn’t exist. 

After all, how did human communication originate? – it’s a question that academics are still trying to figure out. The question I was really asking turned out to be much bigger than I’d previously thought. I wasn’t just asking where the hazard flash came from, I was asking how the hazard flash came to mean “thank you”, and how that became a common understanding between road users. I was asking about the origin of meaning itself. 

I reached out to Dean Alan Jones from the University of Otago, who completed his MA in linguistics in 2018 on the topic of how gestures acquire meaning. 

He told me that “as a communication signal develops, it continues to simplify”. He gave the example of a study he conducted in which participants were asked to represent fishing with a signal. These gestures would start off quite elaborate: “pick[ing] up a fishing pole, tilting it back, casting the line, reeling it in, catching a fish,” but gradually became simpler after repetition. In the case of the fishing mime, participants reduced the sign down to casting the line. 

Huh, I thought. Maybe the trucking company owner’s point about the “good old days” was illuminating after all. If a hand out the window was the old signal, perhaps it gradually simplified over time to a push of the hazard button. Much easier than winding down the window, then sticking a hand out, all while trying to keep an eye on the road. 

Jones also told me that these coded signals spread “similar[ly] to an infection rate. 

“One person decides to use the signal, so tells three other people who tell three others. Another possible way is by clear contextual relevance.”

In other words, a driver who sees another driver flash their hazards after they let them into a queue could logically deduce that it meant “thank you”. See it enough times, and that driver might start using it, spreading that signal to others. 

I felt we were getting tantalisingly close to the truth. 

I asked Jones if he thought the hazard light signal might have multiple simultaneous origins.

“Absolutely,” was the resounding answer. 

“Unlike physical gestures or verbal language, [car] communication is restricted,” says Jones, who notes your options are limited to horns, lights and swerving. “There’s also a limited number of things you’d want to communicate – you might want to say thank you or sorry, ask someone to move faster or slower, or to give them a warning.

“With these limited sets of how and what to communicate, the probability seems pretty high that different, separate groups of people would decide to use the same signal to mean the same thing.” 

Suddenly, it made sense that hazard light flashing had seemingly been around forever, yet only took off recently, and seemed to have originated in Japan, the UK, Ireland, South Africa and elsewhere all at once. Probably because it had. The hazard flash was probably as old as hazard lights themselves. 

Frustratingly, I couldn’t seem to figure out when hazard lights were introduced in New Zealand. Flashing indicator lights only became widespread in the 50s, when they attracted a lot of controversy from champions of ye olde arm signals. But from anecdotal evidence from long-time road users and the internet, the hazard flash notably became a “thing” worldwide in the 80s, and that answer was as good as any. 

Perhaps I’d never get my answer about the origins of the hazard flash. But I could shape the hazard flash’s future by doing my bit to spread the word.