GB1175101A - Traffic Indicator of Congestion on the Roads - Google Patents

Abstract

1,175,101. Road traffic measurements. L'- ECLAIRAGE DES VEHICULES SUR RAIL. 2 Jan., 1967 [31 Dec., 1965], No. 162/67. Heading G4Q. Road traffic congestion is measured by comparing traffic volume with the mean time spent by vehicles in a traffic detection zone. In Fig. 5, the vehicle detector D is preferably a magnetic loop or a radar detector but may comprise road pads arranged to give a signal proportional to passage time. The detector D operates a relay A, which causes a capacitor q1 to discharge into a second capacitor Q1, so that the charge on Q1 is proportional to traffic volume. This quantity is classified into ranges by voltage-sensitive devices L1-L3 which operate respective relays A1-A3 controlling contacts 8-11 and also operating an indicator 12. The detector D also operates a relay B for the duration of the passage time so that a capacitor q<SP>2</SP> discharges into a further capacitor Q2 for this time, so that the charge on Q2 is proportional to the mean passage time. This charge is also dependent on traffic volume, owing to the effect of contacts 8-11, and is classified into ranges by further voltage-sensitive devices L which operate relays B controlling the indicator 13. In a modification, Fig. 6 (not shown), the resistances corresponding to r 1 -r 4 are arranged in series, with the contacts corresponding to 8-11 shunting them. In another modification, Fig. 7 (not shown), the single capacitor q 2 is replaced by a plurality of capacitors which discharge in sequence into Q 2 . In a further modification, Fig. 8 (not shown), a single capacitor q 2 is repeatedly charged and discharged into Q 2 for the duration of the vehicle passage time. In modifications of this arrangement, the potential to which the capacitor q 2 is charged is varied by the relays A 1 of the traffic volume measurement circuit, Fig. 9 (not shown), or the capacitor q 2 is charged from Q 1 , Fig. 10 (not shown), which in this case discharges into q 1 on each operation of relay A so that its charge is inversely proportional to traffic volume.