Out of Town Areas

However, in outer areas, where the traffic flow is lighter and fluctuates a lot more, synchronization is not so important. At these signals vehicles are detected by loops in the road and the green time is apportioned according to the demand on each approach. In this manner delays are kept to a minimum since the side street can be given green as soon as the main street vehicles have cleared.

This is known as the vehicle actuated mode of operation and apart from switching quicker between approaches there is a big difference in the way pedestrians are handled.

With the fixed time operation the pedestrian green man appears every cycle with the corresponding green for traffic so there is no need for pushbuttons - and you will notice this particularly in the CBD. However with vehicle actuation the green man only appears if a pedestrian pushes the button - and it is very important not to cross without doing so. You may see the signal go green for the vehicles in your direction and therefore think it is safe to cross but if there is only one vehicle, say, the signal will change quickly to the other approach and you could be left stranded in the middle of the road.

Outer Areas

• traffic flow light, spasmodic, fluctuates.
• isolated signals, synch not important but delays kept to a minimum
• VA mode - vehicles detected by loops in road
  • green time apportioned according to demand on each approach
  • ped pushbuttons, red man = crossing time