Patent ID: 6496773
Filing Date: 2002-12-17
Classification: G08G

Abstract:
A method for managing traffic in a road network, comprising:a selection of different roads selected from the group consisting of at least one of motorways, larger roads, a thoroughfare, entrance roads, and subareas of the network, wherein subnetworks in city areas include road network of streets with crossings, and where the network includes road links which are connected with each other via nodes, wherein said nodes can connect a variable number of links, and be designed in different ways, wherein said roundabouts are included and various types of intersections; and wherein sensors and control means for traffic are positioned at selected links in the network, and wherein the traffic management includes a task to preserve and utilize a large capacity on selected parts of the road network, wherein capacity at a selected cross section includes the maximum traffic flow which can pass the cross section, and including performing said task during a time period when the traffic volume and need for capacity are large, and wherein the method for traffic management is based on selected basic principles, and is characterized by; a. reducing blocking and risk for blocking of flows on links, whereby blocking is meant cars that standing still or with low velocity wholly or partly are blocking one or several lanes for in-flows or passing through flows on a link; b. performing step (a) by limiting the upstream flow to reduce the risk for blocking downstream link; c1. performing step (a) by determining flow rations for selected parts of the network, and the ration being a target value at the control of the size of a flow to a link or a node; c2. performing step (c1) with application of step (b), where the ration for a link is determined, including a judgment of the risk for blocking of said link; c3. performing step (c2) for selected links in addition of determining the ration for a link, where also the risk for blocking downstream link is judged at the ration determination, and is based on the ration for in-flows to a link being governed by the out-flow from the link, and is the out-flow from the link via downstream node dependent on rations, which are given to exit links from said downstream node, and dependent on limitation, which are given by controlling flows through the node from entrance links of the node to exit links of the node; d1. for a node with at least one upstream link performing step (a) by measuring flows on at least one of this link, other upstream links and downstream links; d2. measurements according to step (d1) being used for the method step of comparing estimated flow values, based on said measurements, with at least one of: assigned rations and settings of control for controlling the out-flow from at least one of upstream links of said node, and when deviations are larger than selected values, performing actions according to at least one of steps (e)-(f) as follows; e. analyzing if said deviaton according to step (d2), indicates that at least one of said links are or will be blocked or has a margin to handle said deviation; and f. assigning corrected settings of the control selecting at least one of: said links and their upstream links.