Puffin Crossing - Function

Function

Unlike the older pelican crossing designs, where the pedestrian signal lights are mounted on the opposite side of the road, the puffin crossing has them mounted at the near road side, set diagonally to the road edge. This allows the pedestrian to monitor passing traffic while waiting for the signal to cross. A second reason for the design is that having the lights closer to the user assists visually impaired people who could have difficulty viewing the signal from across the carriageway.

Some push-button units (the lower box in the picture) are also fitted with a tactile knob under the unit which rotates when the user may cross. This feature is to assist with visually impaired people struggling to see the light change.

After a request to cross (by button press) a kerb-side detector monitors the pedestrian's presence at the crossing. Should the pedestrian cross prematurely, walk away from the crossing, or wait outside the detection area, the pedestrian's request to cross could be automatically cancelled so traffic is not halted unnecessarily.

An on-crossing detector ensures that the signal for vehicles remains red until the pedestrians have finished crossing (within practical limits). Unlike the pelican crossing, there is no transitional "flashing" phase.

A further difference from the pelican design is that, in the puffin design, the time delay between successive pedestrian 'green man' indications begins as soon as the system finishes its cycle, so that a button press will instantly change the traffic lights if the delay period had expired. This differs from the pelican design, in which the delay does not begin until the pedestrian push button is pressed; meaning pedestrians will always have a short wait on pressing the cross button.