Originally Posted by qualla

IANAL but, this seems as if it must be a state by state, or even town-by-town issue. In wisconsin, small vehicles
"...may, after stopping as required under subd. 1. not less than 45 seconds, proceed cautiously through the intersection before the signal turns green if no other vehicles are present at the intersection to actuate the signal and the operator of the motorcycle, moped, motor bicycle, or bicycle reasonably believes the signal is vehicle actuated. "
My impression is that "reasonably" translates to "pretty d*mn sure" - and, sensibly, it only seems to apply if you won't interfere with pedestrians or with traffic that has the green light.