Yeah I've seen it happen once a year - to one signal! It is located here and every winter it gets hit by a side walk snowplow, finally last winter they had the brilliant idea (and it only took 20 years) to put in a taller pole and mount the signal higher (it was an abnormally short pole before) Hopefully this winter the signal won't get hit.
Looks they used one of those mini poles that's used to mount flashers on, can't believe they took 20 years to fix it, especially since it gets knocked down every winter
MTO on the other hand uses full size signal poles just to mount the ped signals on.