GB1192025A - A Method of and Apparatus for Detecting Traffic Delay - Google Patents

Abstract

1,192,025. Road traffic measurements. TATEISI ELECTRONICS CO. 12 Oct., 1967 [20 Oct., 1966], No. 46685/67. Heading G4Q. Traffic congestion is measured by determining the time spent by vehicles in a detection zone, e.g. of an inductive loop detector. The time that a vehicle spends in a detection zone depends on its length and on the length of the detection zone; the total detection time in a given period gives an output equal to the sum of two terms, one proportional to traffic density and the other to average time occupancy, and this is used as a measure of congestion. In Fig. 3, five detectors in five traffic lanes are coupled to terminals 25- 29 so that pulses from a clock pulse generator 22 pass from various stages of a divider 24 to the output gate 38 for as long as any detector is actuated. The output pulses are divided by a counter 40-42, the division ratio of which is variable by the range control switch 47, and by a further divider 30. Divider 30 is set in accordance with the number of detectors used, and with five detectors would divide by five. The output of divider 30 is fed to a classifying circuit comprising counters 72-74 and their associated pinboards; with the latter set as shown the bistables 90-92 are set when the count exceeds 50, 100 and 150 respectively thereby classifying the output in four ranges. At the end of a counting cycle a pulse on line 94 re-sets the counters 72-74 and allows the bi-stables 90-92 to set the output bi-stables 96-98 into the corresponding states, and shortly afterwards a pulse on terminal 100 re-sets the bi-stables 90-92.