Have you ever noticed? when you pull up to a light at an intersection, in the left hand turn lane that there is what looks like a rectangle with a line down the middle, that looks like someone cut into the pavement and then filled it in with a sealant. They look something like this:
There are usually 2 sets of these separated by a car length. They are designed so that if there are 3 or more cars at the intersection they will get the green arrow. At some intersections there are only one and are used to let the traffic light control computer know that a car is present at a low traffic intersection. However at the intersections with 2 you can control the leading left arrow. Here is a real world intersection at 24th st. and Thomas.
The sensors are marked in white in their approximate locations for southbound traffic. Note that at this intersection the sensors are close enough that a sufficiently long vehicle can demand the left arrow all alone (I can do this in my truck). So.... How does this work, well it goes something like this. 1 vehicle must stop on each sensor at or before a preset time before the east/west traffic gets a red light. My experience is, that this is about 1 minute. Now you say "how can I control the green arrow?" Simple, If you are the first to arrive at the intersection stop far enough back so that any other vehicle that comes up behind you is forced to stop on the second sensor, like this:
You are the red car. You stop far enough back so the the silver car has to stop on the second sensor. If you both trip the sensors before the east/west traffic gets a red light you will get the green arrow. Now suppose you pull up to the intersection and there is already a car at the intersection. Since it is very likely that the person doesn't even know about the sensors he will stop all the way forward. If you were the average clueless driver you would pull up directly behind him and not get the green arrow. This is what you should do:
Once again you are the red car. The silver car is all the way on the front sensor, if you were to pull up right behind him there would not be enough metal over the second sensor to trigger it. Once again if you get there soon enough you get the arrow. These sensors can be triggered by motorcycles, and I have read that bicycles will also if they are large enough and are made from steel. Motorcycles and Bicycles must stop on the center of the sensor to have any chance of a trigger. These intersections are all over town. I have used this technique successfully for years. Now go forth and control the traffic lights, don't let them control you.
Thus endeth the lesson.