The reality is that running red lights is often safer than waiting for a green. Taking off surrounded by motor vehicles is not a safe practice. If you get a chance to avoid having to deal with motor vehicles you should take it for safety’s sake.

Japan seems to lead the way in this respect by having bike lanes across pedestrian crossings. It means you can turn left at red lights and more importantly you can join in with pedestrian crossings instead of waiting in the middle of busy intersections to turn right.

The motor vehicle always hurts the cyclist, its absurd to expect cyclists to obey the same rules as motorists.

At the risk of paraphrasing Jack, we are people, not automatons, as such we should behave with courtesy and use our discretion when ever we interact with our fellow man.

For all those who follow the law to the letter I refer them to a cautionary ditty from the 19th century, it relates to the advent of steam launches on the Thames:

Here lies the grave of Mike O’Day
Who died maintaining his right of way.
He right was clear his will was strong.
But he’s just as dead as if he’d been wrong.

Isn’t it possible that even though our country is democratic and among the more reasonable countries in the world, we may have some laws which don’t conform to natural/moral law?

Recreational use of drugs, consenting sex between 15 year olds, assisting the suicide of the terminally ill, camping out on open land… These are all examples of things which are strictly speaking against the law but where, in many people’s opinion, the current law cuts across the grain of natural morality.

Stealing a bike is clearly against both the human (civil) law and against natural law as it involves harm being done to another. I just don’t see the harm that’s done by running red lights, subject to taking due care and attention. Eventually I’d like to see the law changed so that red lights applied in a different way to cyclists, so we could treat them as yield signs. In the meantime, I’ll do what I think is right and considerate.

Sorry but I don’t think you can pick and choose.

Jack’s original blog is a very good one but I doubt whether an analysis of the science involved would be very rewarding.

The time “saved” is simply the time for which the lights stay red. This would be easy to estimate for one cyclist on a fixed journey but very difficult to quantify over all cyclists in any one day. I suppose some kind of estimate could be made but, as the Chinaman said on seeing his first 100-metre sprint, “Please, what do you do with time saved?” There might be an economic argument for people doing deliveries or taking messages on a bike.

The energy involved is fairly easy to calculate using E = 1/2 x M x V squared:

Slowing down from a speed, V, of 10 metres/second, a cyclist and machine of mass 80kg would lose 4000 joules. This is converted almost entirely into heat energy by the friction of the brakes resulting in a very slight warming of the atmosphere. It would be interesting to devise a means of using the energy to drive a dynamo that would charge up a battery for the cycle lights. To do this without using the brakes however would mean that slowing down would take much longer.

Starting up from rest to get to the same speed would involve the same energy.

Pulling up behind or alongside a lorry involves a simple bit of optics. If you, the cyclist, can see the lorry driver in his mirror, then he can see you. If you can’t see him, then he can’t see you. Know this and act accordingly!

@mike1727: I don’t campaign against law-breaking driving, I campaign against dangerous driving. I think there’s a difference.

I was a cyclist, and didn’t run red lights, not out of any sense of smugness, but I just think that cyclists and motorists have to share the road and all follow the same rules. The other day when crossing the road, I had to stop halfway to avoid being hit by a cyclist who was running the red light – a pedestrian stopping while the green man was illuminated to let traffic go by!

Regardless of how safe or unsafe it is, it comes down to the fact that running red lights is illegal. I also believe that when drivers see it happening, their opinion of cyclists goes down a little, and they might be just a little less aware or careful next time they’re driving near one. This of course could have fatal consequences.

Cheers

Tim

My own commute is 5k and there are 11 sets of lights, some of which will be green (NB this assumption never seems realistic…); so lets say I hit a red light every 1k on average. I’ll compare the time taken for 1k at constant speed versus 1k from a standing start at the same, constant, power; since effectively the stop/start time is just 5x this 1k time. I’ll assume I stop suddenly then the light immediately turns green, so the time doesn’t include waiting at lights.

At 150W, starting at 0m/s, it says I’ll take 119.6s per km. The steady-state speed at 150W is about 9.3m/s, which will take 107.5s. So, roughly 10% s more time, and since this is constant power, 10% more energy.

That speed (around 20mph) is a bit unrealistic, most commuters will be going more like 15mph: 6.7m/s. Sticking in the figures to make that work turns out to need just 66W (this model takes no account of efficiency, so the power figures aren’t realistic). That changes the times to 149.1s versus 163.8s. A slightly smaller difference, as you’d expect from the lower air resistance.

However, 10% difference in energy isn’t very much on a short commute like this. One biscuit would cover it.

http://socrates.berkeley.edu/~fajans/Teaching/bicycles.html

Ride on the road, follow the rules. Ignore the rules with similar reasoning to speeding drivers and perpetuate the lycra lout myth for the media to beat us with.

Stopping (and unclipping) is not unreasonable where the road to the intersection is clear and the cyclist has enough warning time to complete these actions (for example, if the light turns red while the 10mph cyclist is 30-40 feet from the stop line). In urban traffic, and some suburban traffic, the status of the light is not visible through motor traffic, and the only “red light” warning a cyclist gets is the brake lights of the cars in front of him/her. Usually this is insufficient warning to stop in the queue, requiring the cyclist to coast-and-brake in the door zone until s/he gets to the stop line (and the front of the queue). Unfortunately for cyclists, stopped traffic is also a cue to pedestrians to come out from the cars parked at the curb and jaywalk between the temporarily-stopped cars, adding the hazard of a bicycle-pedestrian collision in this time interval.

The issues of lead time, door zones, and pedestrian safety aside, the potential (or lack thereof) for time savings depends on the cyclist’s time-and-distance required for stopping and starting, his/her cruising speed, and how the sequence of lights is timed. For example, two lights in my town, a block apart, are timed such that while traveling north, if I start off from the stop line the instant the first one turns green, I will be stopped by the second light unless I can accelerate to 15mph or greater within 5 seconds. (In practical terms, this means I will always be stopped by both lights.) This suggests that in absence of cross traffic, it should be possible to make time by running lights. (In reality, there is always cross traffic at both these intersections, making it unsafe for a cyclist to attempt to run a light. Not that I don’t see sidewalk-cycling, helmetless immigrants with packages hanging from both wrists doing it regularly.)

Learning to track stand will help move off more rapidly, but no idea on the energy aspect.

Good podcasts, thanks.

Bicycles, Rolling Stops, and the Idaho Stop from Spencer Boomhower on Vimeo.

And Joel Fajans has done the theory stuff re conserving energy on a bike etc.

http://www.arch.ksu.edu/seamon/Fajans.htm