Method and system for obtaining traffic information using transponders

1 . A method of obtaining traffic information regarding a roadway using a vehicle equipped with a transponder having a memory, the roadway including a downstream reader having a downstream communications zone over a first portion of the roadway and an upstream reader having an upstream communication zone over a second portion of the roadway, the upstream communication zone being separated from the downstream communication zone by a distance of the roadway, the roadway including a display sign, the method comprising the steps of:

sending a time stamp to the transponder for storage in the memory of the transponder while the vehicle traverses the upstream communication zone;

reading said time stamp from the memory of the transponder when the vehicle is in the downstream communication zone; and

determining a travel time from the upstream communication zone to the downstream communication zone based upon said time stamp, and travel time information based upon said travel time.

2 . The method claimed in claim 1 , wherein said step of determining includes averaging multiple travel times accumulated from multiple transponders.

3 . The method claimed in claim 1 , wherein said roadway includes a display sign and wherein said method further includes a step of sending said travel time information to said display sign for display.

4 . The method claimed in claim 3 , wherein the display sign is located proximate the upstream reader, and wherein the display sign displays content in response to said travel time information.

5 . The method claimed in claim 3 , wherein said travel time information comprises a quantitative measure of travel time, and wherein the display sign displays said quantitative measure.

6 . The method claimed in claim 3 , wherein said step of sending includes transmitting a digital message via a wireless network.

7 . The method claimed in claim 9 , wherein said digital message comprises an SMS message.

8 . The method claimed in claim 1 , wherein said step of determining includes assigning a qualitative assessment of traffic conditions based upon said travel time, and wherein said travel time information comprises said qualitative assessment.

9 . The method claimed in claim 1 , wherein said step of sending a time stamp includes sending a programming signal to the transponder, wherein the memory of the transponder includes a locked portion and an unlocked portion, and wherein said time stamp is stored in said unlocked portion in response to said programming signal.

10 . The method claimed in claim 1 , wherein said downstream reader performs said step of determining.

11 . The method claimed in claim 1 , wherein said step of sending includes sending a location ID for storage in the memory of the transponder, the location ID corresponding to the upstream reader, and wherein said method further includes a step of checking whether said memory of the transponder includes said location ID corresponding to the upstream reader prior to said step of determining.

12 . A system for obtaining traffic information regarding a roadway upon which vehicles equipped with transponders travel, the transponders each having a memory, the system comprising:

a downstream reader having a downstream communications zone over a first portion of the roadway; and

an upstream reader having an upstream communication zone over a second portion of the roadway, the upstream communication zone being separated from the downstream communication zone by a distance of the roadway, the upstream reader having a time stamp transceiver for sending a time stamp to the transponder for storage in the memory of the transponder while one of the vehicles traverses the upstream communication zone,

wherein said downstream reader includes

an interrogation transceiver for reading said time stamp from the memory of the transponder when the vehicle is in the downstream communication zone, and

a travel time module for determining a travel time from the upstream communication zone to the downstream communication zone based upon said time stamp, and determining travel time information based upon said travel time.

13 . The system claimed in claim 12 , wherein said downstream reader includes a memory storing travel times accumulated from multiple transponders, wherein said travel time module averages said stored travel times to produce an average travel time.

14 . The system claimed in claim 12 , further including a display sign visible from at least a part of the roadway, and wherein said downstream reader includes a communication module for sending said travel time information to said display sign.

15 . The system claimed in claim 13 , wherein the display sign is located proximate the upstream reader, and wherein the display sign displays content in response to said travel time information.

16 . The system claimed in claim 13 , wherein said travel time information comprises a quantitative measure of travel time, and wherein the display sign displays said quantitative measure.

17 . The system claimed in claim 13 , wherein said travel time module selects a qualitative assessment of traffic conditions based upon said travel time, and wherein said travel time information includes said qualitative assessment, and wherein said display sign displays said qualitative assessment on the display sign.

18 . The system claimed in claim 13 , wherein said communication module sends said travel time information in a digital message via a wireless network.

19 . The system claimed in claim 18 , wherein said digital message comprises an SMS message.

20 . The system claimed in claim 12 , wherein the memory of the transponder includes a locked portion and an unlocked portion, and wherein said time stamp is stored in said unlocked portion in response to a programming signal from said time stamp transceiver.

21 . The system claimed in claim 12 , wherein said time stamp transceiver sends a location ID for storage in the memory of the transponder, the location ID corresponding to said upstream reader, and wherein said travel time module verifies that the memory of the transponder includes said location ID corresponding to the upstream reader.

22 . A downstream reader for use in a system for obtaining traffic information regarding a roadway upon which vehicles equipped with transponders travel, the transponders each having a memory, the system including an upstream reader having an upstream communication zone and storing a time stamp in the memory of a transponder while a vehicle traverses the upstream communication zone, the downstream reader comprising:

a downstream antenna having a downstream communication zone over a portion of the roadway;

an interrogation transceiver connected to said downstream antenna for sending an interrogation signal to the transponder and receiving a response signal, wherein the response signal includes said time stamp; and

a travel time module for determining a travel time from the upstream communication zone to the downstream communication zone based upon said time stamp and travel time information based upon said travel time.

23 . The downstream reader claimed in claim 21 , wherein said downstream reader includes a memory storing travel times accumulated from multiple transponders, wherein said travel time module averages said stored travel times to produce an average travel time, and wherein said travel time information comprises said average travel time.

24 . The downstream reader claimed in claim 21 , wherein said travel time module selects a qualitative assessment of traffic conditions based upon said travel time, and wherein said travel time information comprises said qualitative assessment.

25 . The downstream reader claimed in claim 21 , wherein said system further includes a display sign proximate said roadway, and wherein said downstream further including a communication module for sending said travel time information to said display sign.

26 . The downstream reader claimed in claim 25 , wherein said communication module sends said travel time information in a digital message via a wireless network.

27 . The downstream reader claimed in claim 26 , wherein said digital message comprises an SMS message.

28 . The downstream reader claimed in claim 21 , wherein the upstream reader stores a location ID in the memory of the transponder, the location ID corresponding to the upstream reader, and wherein said travel time module verifies that the memory of the transponder includes said location ID corresponding to the upstream reader.