Re: Jay-walks then crossing. Some crossing and junctions skip the pedestrian stage when there is no one waiting even if the button was previously pressed. They have crossed in a gap, demand/button cancelled by detector.
The problem is curtailing the "Walk light" is that no detector is 100% reliable, so (say) if a visually impaired pedestrian is crossing and not detected, it raises as big safety concern.
The problem is curtailing the "Walk light" is that no detector is 100% reliable, so (say) if a visually impaired pedestrian is crossing and not detected, it raises as big safety concern.