Method of traffic congestion estimation

Patent metadata

Field	Value
Publication number	US-9449509-B2
Application number	US-201113807229-A
Country	US
Kind code	B2
Filing date	Jun 2, 2011
Priority date	Jun 29, 2010
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

Disclosed is a method of traffic congestion estimation including a speed detection step of detecting speed of a vehicle in a predetermined period of time and outputting the detection result; a frequency analysis step of analyzing a frequency of the result of the speed detection and outputting the power spectrum; a slope detection step of detecting a slope of a power spectrum and outputting the detection result; a time variation calculation step of calculating time variation of the slope and outputting the calculation result; and a traffic congestion estimation step of estimating occurrence of traffic congestion from the calculation result of the time variation of the slope and outputting the estimation result.

First claim

The invention claimed is:

1. A computer-implemented method of traffic congestion estimation in a vehicle, comprising:
detecting, by a sensor, a speed of a host vehicle in a predetermined period of time and outputting a speed detection result;
analyzing, by a processing device installed in the vehicle, a frequency of the speed detection result and outputting a power spectrum that dynamically changes according to the frequency of the speed detection result;
detecting, by the processing device, a slope of the power spectrum in a predetermined frequency range and outputting a slope detection result; calculating a spectrum of time variation of the slope within a predetermined time interval and outputting a time variation calculation result;
estimating, by a navigation device, an occurrence of traffic congestion based on a current position of the host vehicle obtained from a global positioning system and the time variation calculation result of the slope, and outputting an estimation result;
wherein the estimating comprises:
in response to detecting that an extreme value of the spectrum of the time variation of the slope is greater than or equal to a predetermined value, determining, by the processing device, a speed variance of the host vehicle indicating that a traffic congestion is likely to occur due to an increasing number of vehicles in front of and in a traveling direction of the host vehicle; and
in response to detecting that an extreme value of the spectrum of the time variation of the slope is less than a predetermined value and detecting traveling conditions of vehicles in front of and in the traveling direction of the host vehicle, determining, by the processing device, a speed variance of the host vehicle indicating that a traffic congestion is uncertainly to occur due to a decreasing number of vehicles in front of and in the traveling direction of the host vehicle; and
canceling an execution of a vehicle distance adjustment operation which automatically adjusts a vehicle to vehicle distance between the host vehicle and a preceding vehicle when the estimation result indicates the occurrence of the traffic congestion.

2. The method of traffic congestion estimation according to claim 1 , further comprising:
detecting a plurality of extreme values from the time variation calculation result of the slope and outputting an extreme value detection result;
detecting, by a radar device, a number of other vehicles and inter-vehicular distances between the host vehicle and the other vehicles and outputting a vehicle detection result; and
calculating, by the processing device, a probability P(BIX) and a probability P(AIX) to estimate an occurrence of traffic congestion by using Bayes' theorem as follows:

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Assignees

• Koshizen Takamasa
• Eguchi Junji
• Nishinari Katsuhiro
• Honda Motor Co Ltd
• Univ Tokyo

Inventors

• Koshizen Takamasa
• Eguchi Junji
• Nishinari Katsuhiro

Classifications

• G08G1/052

  with provision for determining speed or overspeed {(speed measuring in general G01P)} · CPC title

• B60W2756/10

  Involving external transmission of data to or from the vehicle · CPC title

• B60W2554/801

  Lateral distance · CPC title

• B60W2754/30

  Longitudinal distance · CPC title

• B60W40/04

  Traffic conditions · CPC title