Procedures and arrangements for ensuring the intervals required for the operation of a road signalling system at a crossing

摘要

A method and apparatus for securing the intermediate protective time periods at an intersection in a street traffic signal system to provide adequate safety protection between respective traffic flows, in which, following the end of the duration of the green light time period of individual signal of the respective traffic flows to be independently controlled, the time elapsing thereafter, representing an actual time value, is totaled and compared with predetermined theoretical protective time values for traffic flows antagonistic to the green light signal to be connected, and upon attaining and/or exceeding the predetermined values, an associated connect command to said last-mentioned green light signal is released, and adding, at intervals somewhat smaller than those corresponding to the time rhythm of the traffic signal, all of said theoretical time values, thus forming an additional actual total time value, which is compared with a theoretical total time value therefor, and in the event an error is ascertained by said comparing operations, effecting corresponding safety precautions.