I'm sure there are other threads but I can't seem to find it in the search option.

Where I'm riding I often find myself waiting for the traffic light to change even if my place my bike where the sensors are.

There is always traffic going east and west. My light won't change unless there is a car behind me or there are cars waiting on the other side. and some times cars never show up or they do but they are turning right.
Late at night when I'm riding and there are no cars I will roll up to the light and it will change. What's up with that?

What do I do?