Most cyclists who "run" red lights are in fact treating them as give way or stop signs – they lose much, if not all, of their momentum, make sure the way is clear, and then cycle through. Such behaviour is illegal and can be very costly – for example, the offence carries a whopping $352 fine in Victoria. So why do some cyclists do it? Here are a few likely reasons: Because light signals often don't work for bicycles. Sensors under the road surface are designed to detect big, metal cars and cyclists can find themselves marooned at a light that will never change.

To get out of the way. A bike rider moving off early is often doing cars a favour. Cyclists are at their most vulnerable and obstructive when going from a standstill – they're slow and more liable to weave from side to side. By getting an early start, the bike is travelling steadily and at speed when the cars catch up, making for easier, safer passing.

To avoid pinch points. On most two-lane roads, cars park on the left-hand side just 15 metres after the intersection. Two lanes of cars have to jockey and merge into one lane at this point. Add a cyclist into that (often aggressive) mix and it's obvious who will likely come off worst.

To maintain momentum. As a recreational cyclist, I don't mind red lights – I treat repeated accelerations as part of my workout. But commuter cyclists aren't looking to raise a sweat, and some opt to maintain a bit of momentum by treating a red light as a give way sign. Lastly, and perhaps most importantly, a lot of cyclists do it simply because they get away with it.

They don't see it as a danger to others. Sneaking across an intersection in a car risks injury to people in other vehicles – but by and large, a cyclist who gets it wrong will only injure themselves.

"When I'm a cycling commuter, I see myself as a form of pedestrian," a colleague told me this week. "Pedestrians are far less likely to obey traffic signals than cyclists – but because almost everybody jaywalks, people aren't so upset about it." He's right. Stand on any urban street corner and you'll see flagrant, outrageous lawbreaking by pedestrians. It's just as illegal, but people are seldom fined. And pedestrians who begin to cross when the "red man" is flashing cause far more delays for motorists than any red-light-jumping cyclist. The red light issue is a favourite obsession for those who believe bicycles should be registered – a tedious notion dismissed in a previous blog. Sure, a (yet to be invented) visible licence plate would mean lawbreakers could be caught by traffic camera. But as only a minuscule percentage of traffic lights have cameras, registration makes no sense. And eyewitness accounts of such violations are never going to result in a conviction (trust me on this). There have been some interesting attempts to address the issue in other countries. London's mayor, Boris Johnston, suggested a law that would allow cyclists a legal "left turn on red" signal – but the idea proved unpopular. Then there's the fascinating "Idaho Stop Law" that has been in place for 27 years without any carnage. This video gives some excellent insights into cyclist behaviour.

Several years ago I took a conscious decision that I would always obey red lights. It helps that I'm a confident cyclist in traffic and I don't much mind the waiting or the workout. I see riding in a law-abiding fashion as a public relations exercise and would strongly encourage other cyclists to do the same. But if you're a motorist who gets steamed when you see a cyclist disregard a red light, ask yourself: "How does it affect me?" Sure, if they've nearly caused an accident, that's a problem. But if they're just getting ahead while you sit idling in traffic, I'd suggest there are more important things to get worked up about. After all, when I'm in a car, I'd rather share the road with a watchful cyclist going through a red light than a motorist driving while texting, any day of the week.

Do you obey or disregard red lights while cycling? What are your reasons? Follow Michael O'Reilly on Twitter

