But what exactly do these driving deviations look like for two common functions: honking the horn and flashing headlights? BBC Autos sifted through responses on Quora.com, the question and answer community, for first-hand perspectives from across the globe.
Honking is not just about displeasure
When it comes to the horn, usage is rampant worldwide even if the reasons for sounding off vary. Quora user Jan Leadbetter wrote, "Honking the horn in England is a sign of the honker's discontent, or road rage, take your pick."
Americans may be able to relate, but maybe not as much as drivers in India. Tamanna A Shaikh said, "In India, honking is used very liberally. Imagine a noisier, angrier New York City where everyone is driving like a cab driver." She added that in such conditions, “honking is used mainly to ask the driver ahead to move over or drive faster."
Sabarish Bharadwaj elaborates, noting that honking in India is a big – and sometimes the only – way to communicate with other drivers. "We don't stop or slow down at intersections, we honk (or just flash the beams at night),” he wrote. “If there's another vehicle coming to the intersection, they respond with their horn, and then you slow down."
But not all drivers are quick to communicate through the steering wheel. Stewart Alsop, who claims to have ridden motorcycles all over the world, said that in Bangkok, Thailand, there's virtually no horn-honking. "Even though Bangkok traffic jams often last hours in the dreadful heat and humidity, you almost never hear anyone honking a horn. It is considered incredibly rude to honk your horn unless it is absolutely necessary."
To flash or not to flash?
Just as horn usage varies by country, drivers around the world aren't satisfied with using headlights just to illuminate the roadway.
UK drivers are only supposed to flash their headlights to make other drivers aware of their presence. According to Gov.uk, "Only flash your headlights to let other road users know that you are there. Do not flash your headlights to convey any other message or intimidate other road users."
That differs from driving norms in South Africa. According to the country’s driving laws, it is acceptable for a driver who wants to pass another vehicle to flash headlights to communicate the intention of overtaking. Quora user Terence Afer says that once the passing is complete, etiquette compels the overtaking car “to flash the emergency indicators as a 'thank you.'" The overtaken then flashes high beams to acknowledge receipt of the thanks.
Trevor Best says Australian drivers use headlights to warn drivers if something is wrong with the oncoming car – a burned-out headlight bulb, for example. "Some people also use it to warn that some unexpected speed-detection activity is taking place ahead, but only a few people do that as it's illegal," he added.
These norms should sound familiar to drivers in the US, where there is no threat of police prosecution. A federal judge ruled earlier in 2014 that it is a driver's right, under the US Constitution’s First Amendment, which governs freedom of expression, to flash headlights to warn other drivers of speed traps.
So bear in mind that the next time you drive down foreign motorways, cultural differences spill over into driving etiquette. And if you are in the US, would you be so kind to give a heads-up about that police cruiser round the bend?
If you would like to comment on this or anything else you have seen on BBC Autos, head over to our Facebook page or message us on Twitter.