| 摘要 |
A long-standing problem in traffic control is optimization of the flow of vehicles through a given road network. The present invention describes the network system wide control by means of which real time adjustments of the timings of all signals in a traffic network are made in such a way as to achieve an overall reduction in congestion conditions. First, signals obtained from vehicular-based cellular phones and from GPS based technology whenever available are used for collecting location information on moving vehicles. This location information is obtainable from wireless location systems such as GSM in Europe, CDMA in the USA, or PDC in Japan, and depends on supporting technologies, which are in the process of perpetual improvement. It is further used as an input for an Intelligent Traffic Control System that utilizes the cellular network's capabilities to provide sufficiently reliable position information that is stored in the form of records of vehicle phone coordinates, time stamps, etc. Those records together with detailed digital maps are used by mathematical models and algorithms that compute actual travel times consumed by traveling along road sections, by queuing near signalized intersections, and by making various allowed turns and go-throughs in the vicinity of signalized intersection areas. The actual travel times measured for a fixed control time period and reflecting travel congestion, are compared to the corresponding theoretical travel times and form a basis for a certain mathematical optimization model. Maximization of that model allows computation of adjusted phase timings for all signalized intersections within a given area in such a way as to optimize vehicular flows for the next control period and thereby to improve on the congested traffic conditions.
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