Is there a percentage over the speed limit on the gatso speed camera before it activates?

Research shows that you can go a few mph over the limit without being caught by a speed camera.For instance, if the limit is 35mph and you are driving at 37mph you would get away with it. You can get away with being around 1-4% over the limit which, although isn't that much, is better than being caught for going 1mph faster than the limit.