Patent ID: 8428858

Claim:
A traffic jam state calculation system comprising: a controller that: obtains probe information, the probe information comprising an average speed of probe cars traveling on each of a plurality of links in a predetermined area; compares the average speed of each of the plurality of links with each of a plurality of thresholds, each of the plurality of thresholds having a different value; based on the comparison, detects, for each of the plurality of links, a first degree of a traffic jam corresponding to the link for each of the plurality of different thresholds; obtains traffic jam information concerning the plurality of links, the obtained traffic information comprising a second degree of the traffic jam corresponding to each of the plurality of links; compares, for each of the plurality of links, the second degree of the traffic jam with the first degree of the traffic jam for each of the thresholds; selects, for the predetermined area, a threshold from the plurality of thresholds for which the first degree of the traffic jam most matches the second degree of the traffic jam, the threshold usable to differentiate a degree of the traffic jam in the predetermined area; and utilizes the selected threshold to determine a severity of the traffic jam for each of the plurality of links.