| 摘要 |
The essence of the method resides in that an optical signalling is carried out to display the remainder on time of three green or red lights which are suspended over a roadway in a single horizontal row on both sides of the orange light. Then two lights of the effective color are alternately switched off at a preset time interval, beginning with the light most removed from the orange lamp, this being done from a preset instant of time till switching on the orange light, while the third light of the effective color remaining switched on for some period of time. Next two switched off lights are switched on again, and the lights are flashing for the remaining period of time in the following sequence: first all the three lights are flashing in synchronism, then two lights and one light, respectively, flash at regular time intervals, after which the orange light goes on. |
