Electronic traffic control system

• US 4,023,017 A
• Filed: 05/21/1975
• Issued: 05/10/1977
• Est. Priority Date: 05/28/1974
• Status: Expired due to Term

• Current Assignee: Atlantia SpA
• Original Assignee: Atlantia SpA
• Inventors: Ceseri, Pierluigi
• Primary Examiner(s): Dildine, Jr., R. Stephen
• Application Number:
  US05/579,405
• Time in Patent Office: 720 Days
• Field of Search: 235/150.2, 235/150.24, 235/150.27, 325/117, 325/312, 325/314, 340/32, 340/38 R, 340/172.5, 343/7 A, 343/7 VC, 343/7 VM, 343/112 C
• US Class Current: 701/118
• CPC Class Codes: G08G 1/00 Traffic control systems for road vehicles arrangement of road signs or traffic signals E01F9/00 ; automatic vehicle control B62D
• CPC Class Codes: G08G 1/0104 Measuring and analyzing of parameters relative to traffic conditions

Abstract

A traffic control system having a number of detectors spaced along a roadway being monitored. The detectors are organized in groups, each group being interconnected to a different post. The posts include transmission and reception equipment for communicating with the detectors of that group. A transmission line system has a number of sections with a single section corresponding respectively to a single group of detectors. The sections of the transmission line system are also respectively coupled to the posts. The posts are also organized into groups, each group being interconnected to a control computer. All the control computers are connected to a central computer and an operating center. The various computers can be set to control the traffic in response to the information detected. Also, communications can be carried out, both in code and in clear, between the vehicles using the roadway and the computers or the operating center.

Claims

1. An electronic traffic control system for monitoring a stretch of road and permitting two directional transmissions both in code and in clear between an operating center and vehicles located on the stretch of road comprising:

a plurality of detectors positioned in spaced apart relationship along said stretch of road for detecting traffic information and highways conditions;

a plurality of post circuit means, each post circuit means respectively interconnecting a different group of said detectors, each of said post circuit means including means for transmitting and receiving signals from each of the individual detectors constituting that group of detectors;

a radiating system divided into a plurality of sections corresponding in number to the plurality of post circuit means, one section for each of said groups of detectors, said radiating system including a transmission system and receiving and transmitting apparatus positioned respectively in said post circuit means and coupled to said transmission system,

a plurality of control computer means, each control computer means respectively interconnecting a different group of post circuit means, each of said control computer means capable of receiving the detected information from each post circuit means within that group of post circuit means and in response thereto calculating the anticipated traffic information at each of the other post circuit means within that group, comparing the anticipated traffic information with the actual detected information at each of the other post circuit means and upon detecting differences greater than predetermined threshold providing an alarm signal;

visual displays positioned along said stretch of road under control of said alarm signal;

signal devices adapted to be inserted within vehicles utilizing said stretch of road and being activated under control of said alarm signal;

each of said control computer means also controlling the sections of said radiating system within that group of post circuit means to transmit in clear prerecorded messages, specific messages both in code and in clear, and broadcast programs;

an operating center coupled to said control computer means for setting the controls desired on the stretch of road;

a central computer interconnecting said control computer means for providing instructions to each of said control computer means concerning said thresholds and other information, and for storing information regarding the performance of each of said control computer means; and

a manually operated device attached to each of said post circuit means for transmitting code messages to said operating center.

2. The system as in claim 1, wherein said detectors operate on radio frequency signals, and provide an output signal whose amplitude is proportional to the size of a vehicle detected along said stretch of road and whose length is proportional to the duration of the vehicle'"'"'s presence along the stretch of road, each of said detectors including a transmitter and a receiver and operating on a predetermined wave length.

3. The system as in claim 2 and wherein said wavelength is approximately the size of a vehicle of about 3 to 4 meters in length.

4. The system as in claim 2 and wherein said transmitter and receiver are both positioned on the same side of the roadway and the receiver picks up a reflected signal from the transmitter.

5. The system as in claim 2 and wherein said transmitter and receiver are positioned on opposite sides of the roadway facing each other and the receiver picks up an attenuated direct wave from the transmitter.

6. The system as in claim 2 and wherein each detector includes a single transmitter positioned centrally in a two-way road, and a pair of receivers positioned on either side of the roadway.

7. The system as in claim 2 and further comprising telephone lines interconnecting each control computer means with its corresponding group of post circuit means, said control computer means providing a synchronization signal onto said telephone line which controls the wavelength of operation of the transmitters and receivers of the detectors, a first interface attached to each post circuit means which interconnects the transmitters of each detector with said telephonic lines to receive the synchronization signal, and asecond interface attached to said post circuit means which interconnects the receivers of each detector with said telephonic lines to couple the detected signal onto the telephonic lines, and wherein the detected signal has a maximum level when there are no vehicles on the stretch of road being monitored and wherein the presence of vehicles causes a modification of the level of the detected signal, the modification being proportional to the size of the vehicle present on the stretch of road.

8. The system as in claim 7, wherein all the transmitters are activated in parallel and all of the receivers detect their respective signals in parallel thereby permitting identification of the detected signals by a sampling process.

9. The system as in claim 7, wherein the detected signals from each individual detector within a group of detectors are serially combined with each other to form a single message, said message being transferred to corresponding control computer means through said telephonic lines, and further comprising third interface means for transferring said single message onto said telephonic lines.

10. The system as in claim 7 and wherein each of said post circuit means further comprises third interface means interconnecting said visual displays with said telephonic lines.

11. The system as in claim 7, wherein at least one post circuit means of each group of post circuit means further comprises meteorological detectors for detecting the meteorological conditions along said stretch of road and third interface means for interconnecting said meteorological detector with said telephonic lines.

12. The system as in claim 7 and wherein said radiating transmission system includes a transmission line balanced on two wires and terminating in its characteristic impedance.

13. The system as in claim 12 and further comprising decoupling means connected between each pair of said transmission wires and said receiving and transmitting apparatus attached to the post circuit means, said decoupling means permitting the utilization of the same radiating system for both transmission as well as reception of signals both in code and in clear, and further comprising at least two filters each for a different frequency wherein one is used for transmission and the other for reception, and for providing isolation between the said receiving and transmitting apparatus and said radiating system.

14. The system as in claim 13 and wherein said transmission in clear is of an inductive kind.

15. The system as in claim 13, wherein the transmitting part of said receiving and transmitting apparatus comprises, a sinusoidal carrier generator whose frequency and phase are controlled by synchronization signals from said telephone lines, an amplitude modulator coupled to said generator, a power amplifier coupled to said amplitude modulator, said power amplifier being controlled by a first and second channel of said telephonic lines, switch means connected between said telephonic lines and said power amplifier to select one of said two channels to thereby allow discrete areas of transmission, said switch being operated by the corresponding control computer means and by said operating center;

and wherein the receiving part of said receiving and transmitting apparatus comprises a modem for transferring onto a third and fourth channel of said telephonic lines information detected by said radiating system and instructions from said manually operated device.

16. The system as in claim 15, wherein the communications in clear on the first, second and fourth channels of said telephonic lines go directly to said operating center and wherein the code messages of the third channel and the code messages of the fourth channel go to the corresponding control computer means.

17. The system as in claim 15 and wherein the channels of said telephonic lines consist of double-wire telephonic cable.

18. The system as in claim 15 and wherein the channels are formed through a multiplexing transmission system.

19. The system as in claim 15 and wherein at least some of the channels are formed of double-wire telephonic cable, and the rest of the channels are formed by a multiplexing transmission system.

20. The system as in claim 1 and wherein the spacing between adjacent detectors is dependent upon the configuration of the roadway, and the speed and density of traffic to be carried on the roadway.

21. The system as in claim 20 and wherein the spacing between adjacent detectors is between 100 and 200 meters.

22. The system as in claim 1 and wherein each of said detectors includes a transmitter comprising a sinusoidal generator, an antenna for sending out signals, a gating circuit interconnecting said sinusoidal generator and said antenna, a synchronization circuit controlling the operation of said gating circuit and activated by the corresponding control computer means, and a receiver comprising an antenna for receiving the signals from the transmitter, an amplitude detector connected to the antenna, a high gain amplifier connected to the amplitude detector and interface means connected to the amplifier and capable of sending out the detected signals, transmitter cables respectively interconnecting the transmitters within each group of detectors for supplying to each transmitter synchronization signals, and receiver cables respectively interconnecting the receivers within each group of detectors for obtaining the detected signals.

23. The system as in claim 22 and wherein said transmitting and receiving cables are double-wire cables.

24. The system as in claim 22 and wherein said transmitting and receiving cables are coaxial cables.