An experiment has been carried out in which observers estimated the intensities which they considered that traffic signals should have under various road conditions by day and by night. The results indicate that peak intensities are required varying between 7 and 28 times those specified in the present British Standard for Road Traffic Control (Electric) light Signals (B.S.505;1939). Present traffic signals already give peak intensities about 2 1/2 to 5 times greater than those in the Standard. In the majority of road situations lower intensities are desirable by night than by day and a two-level system kis desirable switched either by a photoelectric light control or by a clock. On fast open roads where the highest intensities are required (by day) it would probably be necessary to use larger signals (i.e.with a diameter of 12 in. instead of the present 8 in.) The suggestions are broadly in line with existing practice in the U.S.A.
Samenvatting