Vehicle actuated systems
172. When the 1933 Committee made their review most existing installations were of the fixed-time type and vehicle actuated signals had not then progressed much beyond the experimental stage. Subsequently this type of equipment was developed very rapidly and is now adopted almost universally in any new installations. Experience has shown that when adequately maintained, the vehicle actuated systems are reliable, can handle traffic efficiently, and are extremely flexible in their application to different traffic problems. More recently vehicle actuation has been applied successfully to flexible progressive systems co-ordinating groups of junctions.
Detectors should be placed on all roads entering isolated junctions controlled by vehicle actuated signals. The 1933 Committee suggested that in certain circumstances they might be omitted on the more important road at an isolated crossing of a minor road, but subsequent experience has proved this to be undesirable. Normally detectors should be placed between 90 and 110 ft. from the stop line, and bus and tram stopping places which would interfere with this spacing should be moved. At places where high speeds may be expected, different considerations apply.
Pedestrians and light signals
173. Traffic light signals designed primarily for controlling the movement of vehicular traffic also contribute to the safety of the pedestrian in providing opportunities for crossing the carriageway when vehicular traffic is held up. In designing traffic light signal installations the needs of pedestrian traffic should be fully considered and such provision for that traffic as is practicable should be made.
Special signal installations are sometimes provided away from road junctions to facilitate crossing of the carriageway by pedestrians at points where both vehicular and pedestrian traffic are heavy. The modern types of signals are actuated by vehicle detectors placed in the carriageway and by push buttons or similar devices operated by the pedestrians desiring to cross. We recommend the continued use of signals of this type in appropriate cases.
On installations at junctions where pedestrian traffic is regular but not exceptionally heavy, we consider it desirable that additional three-light signals (showing the same signal as the appropriate primary signal) should be provided so that a pedestrian about to cross the road at the junction can see at least one signal immediately facing him. On normal two-phase installations this should not present any difficulty, but where traffic movement through the junction is more complex it may be found in some cases that additional signals would be misleading to drivers (by being visible from a traffic lane not controlled by the corresponding primary signal) or would be dangerous to pedestrians by encouraging them to cross at a time when a substantial volume of turning traffic may be moving across their path.
At signal controlled junctions where pedestrian traffic is heavy it may be desirable to introduce a separate phase for pedestrians, with “Cross Now” signal indications, either by providing a regular all-Red period where pedestrian traffic is heavy and continuous, or by the use of a push-button where pedestrian traffic is intermittently heavy. A separate phase specially introduced for pedestrians must result in increased delay to vehicular traffic, and careful examination of traffic conditions at each junction is necessary in order to determine whether the separate phase is practicable and justified.
We note that in Circular No. 544 (Roads) issued in February, 1940, the Minister asked all highway authorities to review existing installations in their areas with a view to making additional provision for pedestrians, on the lines indicated in this paragraph, wherever that course was practicable and
54
