From the back!?!?!?

Help, if I pech I was bled yesterday from behind. is it possible that a bmobile flash from the other side of the road can also flash the traffic on the other side??? it was in the evening and I could not see exactly if the traffic on the other side was in exactly the height where the radar trap was! is it possible that the radar trap can monitor the traffic on both sides???? or is it either just from the front or only from the back or is it going both at the same time ig???