Vehicle on-board unit

1. A vehicle on-board unit comprising:

a vehicle traveling condition detecting section configured to detect at least one vehicle traveling condition of a host vehicle that is equipped with the vehicle on-board unit, with the vehicle traveling condition detecting section monitoring a host vehicle location as part of the vehicle traveling condition to determine a travel lane of the host vehicle using a plurality of detection results of the host vehicle location;

an incoming message receiving section configured to receive a preceding vehicle message containing throttle release data of a preceding vehicle located in front of the host vehicle equipped with the vehicle on-board unit;

an incoming message relevancy section configured to perform a relevancy determination of the throttle release data received by the incoming message receiving section;

a driver warning section configured to selectively alert a driver of the host vehicle of a potential braking situation of the preceding vehicle based upon the relevancy determination of the incoming message relevancy section; and

a relevancy adjustment section configured to selectively adjust the relevancy determination of the throttle release data when the driver warning section alerts the driver of the host vehicle of the potential braking situation of the preceding vehicle based on the travel lane.

2. The vehicle on-board unit as recited in claim 1 , wherein

the driver warning section is further configured to produce a first warning signal to alert the driver of the potential braking situation based upon the relevancy determination satisfying a first condition indicative of a slow throttle releasing action in the preceding vehicle, and to produce a second warning signal to alert the driver of the potential braking situation based upon the relevancy determination satisfying a second condition indicative of a fast throttle releasing action in the preceding vehicle with the first and second warning signals being different.

3. The vehicle on-board unit as recited in claim 1 , wherein

the driver warning section is further configured to produce at least one of a visual warning signal, an audible warning signal and a haptic warning signal to alert the driver of the potential braking situation of the preceding vehicle.

4. The vehicle on-board unit as recited in claim 3 , wherein

the driver warning section is further configured to produce a first visual signal as part of the first warning signal and a second visual signal as part of the second warning signal.

5. The vehicle on-board unit as recited in claim 4 , wherein

the driver warning section is further configured to produce an audible signal as part of the second warning signal in addition to the second visual signal.

6. The vehicle on-board unit as recited in claim 1 , wherein

the vehicle traveling condition detecting section is further configured to detect a following distance between the host vehicle and the preceding vehicle as part of the vehicle traveling condition.

7. The vehicle on-board unit as recited in claim 1 , wherein

the vehicle traveling condition detecting section is further configured to detect a host vehicle speed as part of the vehicle traveling condition.

8. The vehicle on-board unit as recited in claim 1 , wherein

the vehicle traveling condition detecting section is further configured to detect a relative speed between the host vehicle and the preceding vehicle as part of the vehicle traveling condition.

9. The vehicle on-board unit as recited in claim 1 , wherein

the incoming message relevancy section is further configured to perform the relevancy determination of the throttle release data based on an amount of throttle release.

10. The vehicle on-board unit as recited in claim 9 , wherein

the incoming message relevancy section is further configured to perform the relevancy determination of the throttle release data based on a rate of change in the amount of throttle release between two throttle positions.

11. The vehicle on-board unit as recited in claim 9 , wherein

the incoming message relevancy section is further configured to perform the relevancy determination of the throttle release data based on a drop in the amount of throttle release to a closed throttle position within a prescribed period of time.

12. The vehicle on-board unit as recited in claim 1 , further comprising

a vehicle path history generating section that generates a host vehicle path history data indicative of a travel path of the host vehicle.

13. The vehicle on-board unit as recited in claim 12 , wherein

the vehicle path history generating section includes using GPS data of the host vehicle to generate the host vehicle path history comprising a plurality of GPS points.

14. The vehicle on-board unit as recited in claim 12 , further comprising

a two-way wireless communications section configured to receive a preceding vehicle message that at least includes a preceding vehicle path history data indicative of a travel path of the preceding vehicle along the travel lane that the host vehicle is currently traveling; and

a lane centerline determining section configured to determine a lane centerline of the travel lane that the host vehicle is currently traveling based on the host vehicle path history data and the preceding vehicle path history data.

15. The vehicle on-board unit as recited in claim 14 , wherein

the two-way wireless communications section is further configured to broadcast a host vehicle message that at least includes the host vehicle path history data and the preceding vehicle path history data.

16. The vehicle on-board unit as recited in claim 14 , wherein

the lane centerline determining section is further configured to weight the preceding vehicle path history data more heavily than the host vehicle path history data in determining the centerline of the lane.

17. A method for early warning to a host vehicle driver of potential braking situation of a preceding vehicle comprising:

detecting a host vehicle traveling condition of a host vehicle, the detecting of the host vehicle traveling condition at least including monitoring a host vehicle location as part of the vehicle traveling condition to determine a travel lane of the host vehicle using a plurality of detection results of the host vehicle location;

receiving a preceding vehicle message containing throttle release data of the preceding vehicle located in front of a host vehicle;

performing a relevancy determination of the throttle release data that was received by the host vehicle at least partially based on the travel lane of the host vehicle that was determined; and

selectively warning the driver of the host vehicle of a potential braking situation of the preceding vehicle based upon the relevancy determination of the throttle release data.

18. The method as recited in claim 17 , wherein

the warning to the driver of the host vehicle includes producing a first warning signal to alert the driver of the potential braking situation based upon the relevancy determination satisfying a first condition indicative of a slow throttle releasing action in the preceding vehicle, and to produce a second warning signal to alert the driver of the potential braking situation based upon the relevancy determination satisfying a second condition indicative of a fast throttle releasing action in the preceding vehicle with the first and second warning signals being different.

19. The method as recited in claim 17 , further comprising

selectively changing a timing of the warning to the driver based on the vehicle traveling condition.