Traffic monitoring system with reduced communications requirements

Claim 1

A method of estimating quantitive data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for acquiring data from which speed of the calibrant vehicle at different times and locations can be determined; and for transmitting the acquired data to a receiving station, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, h) analyzing said data received from said calibrant vehicles to determine the relationship between the number of said calibrant vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles whose reporting will provide a given reliability of traffic flow estimation, i) then deploying said number of probe vehicles at least one time of day and traffic conditions corresponding to said at least one combination, each probe vehicle having respective means for acquiring data from which subsegment information including the speed of that probe vehicle at different times and locations can be determined, j) in response to predetermined criteria, controlling at least one of said probe vehicles to transmit said subsegment information, and k) computing estimated traffic flow along at least one segment of said route based at least partly on the transmitted subsegment information.

Claim 2

A method of estimating quantitive data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for acquiring data from which speed of the calibrant vehicle at different times and locations can be determined; and for transmitting the acquired data to a receiving station, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, h) analyzing said data received from said calibrant vehicles to determine the relationship between the number of said calibrant vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles whose reporting will provide a given reliability of traffic flow estimation, i) then deploying said number of probe vehicles at least one time of day and traffic conditions corresponding to said at least one combination, each probe vehicle having respective means for acquiring data from which subsegment information including the speed of that probe vehicle at different times and locations can be determined, j) in response to predetermined criteria, controlling at least one of said probe vehicles to transmit said subsegment information, and k) computing estimated traffic flow along at least one segment of said route based at least partly on the transmitted subsegment information.

Claim 10

A method of estimating quantitive data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for determining the location of the respective vehicle at respective instants of time separated by intervals of approximately a given period of time, for determining the time of each said respective instant, and for recording data corresponding to the determined location and said time for each respective instant; and respective means for transmitting the recorded data, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, h) analyzing said data received from said calibrant vehicles to determine the relationship between the number of said calibrant vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles, less than the number of said plurality of calibrant vehicles, whose reporting will provide a given reliability of traffic flow estimation, i) then deploying a second number of probe vehicles at least one time of day and traffic conditions corresponding to said at least one combination, each deployed probe vehicle having respective means for determining the location of the respective vehicle at respective instants of time separated by intervals of approximately a given period of time, for determining the time of each said respective instant, for computing average subsegment speed between the most recent determination of location and the previous determination for that probe vehicle, and for comparing said average subsegment speed with said baseline data having a time-varying bandwidth descriptive of traffic conditions on the segments of said route in which the latest location lies, and for determining whether that average subsegment speed is a normal value falling within said bandwidth for the combination of time of day, segment and traffic conditions, j) responsive to determination that a given probe vehicle's subsegment speed is an abnormal speed not falling within said bandwidth, controlling said means for transmitting in said given probe vehicle to transmit information related to the computed subsegment speed, and k) computing estimated traffic flow along at least one segment of said route based at least in part on the transmitted information.

Claim 11

A method of estimating quantitive data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for determining the location of the respective vehicle at respective instants of time separated by intervals of approximately a given period of time, for determining the time of each said respective instant, and for recording data corresponding to the determined location and said time for each respective instant; and respective means for transmitting the recorded data, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, h) analyzing said data received from said calibrant vehicles to determine the relationship between the number of said calibrant vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles, less than the number of said plurality of calibrant vehicles, whose reporting will provide a given reliability of traffic flow estimation, i) then deploying a second number of probe vehicles at least one time of day and traffic conditions corresponding to said at least one combination, each deployed probe vehicle having respective means for determining the location of the respective vehicle at respective instants of time separated by intervals of approximately a given period of time, for determining the time of each said respective instant, for computing average subsegment speed between the most recent determination of location and the previous determination for that probe vehicle, and for comparing said average subsegment speed with said baseline data having a time-varying bandwidth descriptive of traffic conditions on the segments of said route in which the latest location lies, and for determining whether that average subsegment speed is a normal value falling within said bandwidth for the combination of time of day, segment and traffic conditions, j) responsive to determination that a given probe vehicle's subsegment speed is an abnormal speed not falling within said bandwidth, controlling said means for transmitting in said given probe vehicle to transmit information related to the computed subsegment speed, and k) computing estimated traffic flow along at least one segment of said route based at least in part on the transmitted information.

Claim 17

A method of estimating quantitive pattern data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for acquiring data from which speed of the calibrant vehicle at different times and locations can be determined; and for transmitting the acquired data to a receiving station, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions.

Claim 18

A method of estimating quantitive pattern data describing the flow of traffic, comprising the steps of: a) providing a plurality of calibrant vehicles, b) providing each calibrant vehicle with respective means for acquiring data from which speed of the calibrant vehicle at different times and locations can be determined; and for transmitting the acquired data to a receiving station, c) providing at least one receiving station having means for receiving said data transmitted by respective calibrant vehicles, d) at spaced times approximately equal to predetermined times of a respective day, dispatching a respective calibrant vehicle for operation over a substantially predetermined route, e) during at least the portion of the day that each respective vehicle is being operated over said route, controlling said respective vehicle to record said data, f) transmitting the recorded data to said at least one receiving station, g) computing subsegment speed samples for each calibrant vehicle from which said data have been received, and determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions.

Claim 22

A method of estimating quantitive data describing the flow of traffic along a route, comprising the steps of: a) determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, b) analyzing said baseline data to determine the relationship between the number of probe vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles whose reporting will provide a given reliability of traffic flow estimation, c) deploying a plurality of probe vehicles at respective times approximating the time of day and traffic conditions corresponding to said at least one combination, d) causing each deployed probe vehicle to acquire data from which subsegment information including the speed of that probe vehicle at different times and locations can be determined, to compare subsegment speed with said baseline data having a time-varying bandwidth descriptive of traffic conditions on the segments of said route in which the latest location lies, and to determine whether that subsegment speed is a normal value falling within said bandwidth for the combination of time of day, segment and traffic conditions, e) responsive to determination that a given probe vehicle's subsegment speed is an abnormal speed not falling within said bandwidth, controlling said means for transmitting in said given probe vehicle to transmit information related to the computed subsegment speed, and f) computing estimated traffic flow along at least one segment of said route based at least in part on the transmitted information.

Claim 23

A method of estimating quantitive data describing the flow of traffic along a route, comprising the steps of: a) determining baseline data having a time-varying bandwidth descriptive of traffic conditions on respective segments of said route for at least one combination of time of day and traffic conditions, b) analyzing said baseline data to determine the relationship between the number of probe vehicles and the reliability of traffic flow estimation based thereon, and selecting a first number of probe vehicles whose reporting will provide a given reliability of traffic flow estimation, c) deploying a plurality of probe vehicles at respective times approximating the time of day and traffic conditions corresponding to said at least one combination, d) causing each deployed probe vehicle to acquire data from which subsegment information including the speed of that probe vehicle at different times and locations can be determined, to compare subsegment speed with said baseline data having a time-varying bandwidth descriptive of traffic conditions on the segments of said route in which the latest location lies, and to determine whether that subsegment speed is a normal value falling within said bandwidth for the combination of time of day, segment and traffic conditions, e) responsive to determination that a given probe vehicle's subsegment speed is an abnormal speed not falling within said bandwidth, controlling said means for transmitting in said given probe vehicle to transmit information related to the computed subsegment speed, and f) computing estimated traffic flow along at least one segment of said route based at least in part on the transmitted information.