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The odds of making a green light while riding a bicycle


Road Runner
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After years of random and exhaustive empirical data sampling, the following formulaic theory is confirmed:  

 

The odds of making a green light while on a bicycle are inversely proportional to the square of the average speed displayed on the computer at the time of approach.

O = 4 / S²  ;     O  =  odds of making a green light expressed as a decimal fraction; i.e. 0.25 represents odds of one in four

                         S  =  computer average speed at the time of approach in miles per hour.

                         4  =  cycling karma constant value

 

Example 1:  At an average speed of 8 mph, the odds of making the green would be 4/8² = 0.0625 or odds of one in sixteen. 

Example 2:  At an average speed of 20 mph, the odds of making the green would be 4/20² = 0.001 or odds of one in one hundred.

 

 Notes:   It has been proven that light cycles and length of green is not of any consequence when determining the odds of making a green light.  Also, this formula only applies to speeds of 2 mph and above, as it is deemed nearly, if not impossible, to maintain an average speed below 2 mph.   

 

The results of this theory strongly suggest that if you are maintaining a really good average speed and you are approaching a stop light, you don't stand a chance in hell of making the light.   :(

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Try waiting at a red light while on a bamboo bike. There is not enough metal in my bike to trigger the magnetic strip. 

If the sensors rely on ferrous materials, then I don't think an aluminum or a carbon fiber frame bike will be detected either.

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If the sensors rely on ferrous materials, then I don't think an aluminum or a carbon fiber frame bike will be detected either.

Yup, can confirm there's one a few miles from here where, if there's no car coming up behind me, I have to do the "stop and go". Never tried it on my steel-framed MTB.

But here in town, there's five lights and I can time them pretty well, so the odds of me getting the green or having to do a short trackstand are pretty damned good,

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If the sensors rely on ferrous materials, then I don't think an aluminum or a carbon fiber frame bike will be detected either.

Non ferrous metals will trigger that inductive loop sensor as well as ferrous metals.  It's all based on he setup of the loop sensor.

http://www.humantransport.org/bicycledriving/library/signals/detection.htm

Detection of Bicycles by Quadrupole Loops 
at Demand-Actuated Traffic Signals

"There is a common misconception that an object must be ferrous (include iron) to activate a traffic signal loop sensor, or that a ferrous object will perform better. This misconception is fed by the observation that steel cars are detected by standard loop detectors but small aluminum bicycles often, but not always, are not."

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I'm lucky (or is it unlucky?) in that most of the traffic lights I ride through on the County roads do notice the bike.  I will roll through a stop sign if the coast is clear but I stop at red lights - unless I know it's one that doesn't recognize I'm there.  The signals on the State highways in general seem to do a poorer job of detecting a bike, and they run on long cycles so it can be a long wait.

Since traffic signal design is on my resume, I can sometimes anticipate when the light is about to change and I can sprint to make sure I'm there for the green.  But sometimes I'm quite happy to stop and get a breather.

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On my usual in-city ride, I encounter 18 traffic lights and at least as many stop signs.

It is very hard to maintain a decent average speed unless I cheat the stop signs (which I do) and make most of the lights, which can never happen as a result of the law of probability stated above.  :(

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