| 摘要 |
PURPOSE:To correctly decide the propriety of a calculated travel time by correcting an optimum reference travel time or a reference travel time for every calculation of the travel time and correspondingly correcting the boundary of respective time ranges. CONSTITUTION:A travel time calculating means 17 calculates the travel time based on a signal from the terminal equipments from an upstream side and a down stream side. A discriminating means 19 discriminates to which time range the travel time belongs according to the reference travel time previously written in a storing means 18. This reference travel time is corrected by the average time of calculated the travel time and corrected by a rewriting means 20. When there are prescribed number of time ranges successively discriminated to be the same time range below a time range decided to be a normal travel time by the discriminating means 19, the threshold of the discriminating means 19 is changed by a changing means 21. |
