Advocacy & Safety - red light question

I've heard some lights are not trigged by bikes - just out of curiousity.
If I am on a large trike in the front of line of cars waiting at an innersection for the light to change, would the car behind me trigger the light? Or do I need to get out of the way so they can pull up right under the light so it would trigger?

Have yet to try to drive in traffic so was just wondering how that would work.

Some capacitive loop detectors will not trip by bicycles, and many are programmed to trip shorter when two vehicles (cars) are present.

This is a pretty common question around here. This website has some good information on how to trigger different types of detectors:

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

Your trike will be detected by a properly calibrated/operable detector. If the detector is not properly calibrated it may need a larger hunk of metal (a car) to trigger the light. If a signal fails to change for me and there is a car behind me, I will usually pull forward into the crosswalk and motion at the vehicle behind me to move up onto the detector, but around here most of the lights will change for me on my regular bike (aluminum frame/wheels).

If I am on a large trike in the front of line of cars waiting at an innersection for the light to change, would the car behind me trigger the light? Or do I need to get out of the way so they can pull up right under the light so it would trigger?.
no, there should not be a need for you to "get out of a car's way" as typically there are multiple detector loops (provided you are waiting at a traffic-actuated intersection and not one that is timed) embedded in the pavement, extending at least several car-lengths back from the intersection. The tricky intersections are those where there are no visible saw-cuts in the pavement for the loops. In those instances, it's usually best to position the bike (or trike) over either the left or right tire tracks of where a car would be in the lane when trying to trigger a green light. If there are visible saw-cuts, position your wheels directly over the saw-cut. However, even then, there are occasions where the sensor is not sensitive enough to detect the bike (or trike) and you may have to wait for a car to arrive.

Thanks everyone for the explanation. I was just a little worried about a scenario in which I was waiting at the light in which it doesn't trigger, and causing it not to trigger for cars behind me.. which would probably be less then great for getting along with the motorists.

If you encounter an insensitive detector in your own community or along one of your regular routes, report it to the appropriate traffic engineering department. Some cities, such as Carlsbad CA, are very receptive and responsive (so to speak) to these requests. Unfortunately, certain others are far less enlightened.

- Unfortunately, certain others are far less enlightened.

The city of South Portland Maine would fall into this less enlightened category. There is a left turn signal on my morning commute which does not recognize my steel bike. I wrote the city reporting the malfunctioning light, and got a reply which basically said that it would be too expensive to change the system to be able to detect cyclists. In my view this means that the signal is not functioning properly, and as such is not a signal which I have to obey. Fortunately, I hit that signal early morning when there is little or no traffic, so making my turn against the red arrow is not difficult to do.

^^^^^^Any chance of going over their heads to the state to get it repaired? Does Maine have standards for what is needed to trip the light?

As a side note, the one in front of my house is stone simple to adjust, it takes a few minutes in the control box.