Monitoring Weaving Sections

Executive Summary Traffic control in highway weaving sections is complicated since vehicles are crossing paths, changing lanes, or merging with through traffic as they enter or exit an expressway. There are two types of weaving sections: (a) single weaving sections which have one point of entry upstream and one point of exit downstream; and (b) multiple weaving sections which have more than one point of entry followed by more than one point of exit. Sensors which are based on lane detection fail to monitor weaving sections since they cannot track vehicles which cross lanes. The fundamental problem that needs to be addressed is the establishment of correspondence between a traffic object A in lane x and the same object A in lane y at a later time. For example, vision systems that depend on multiple detection zones simply cannot establish correspondences since they assume that the vehicles stay in the same lane. The motivation behind this work is to compensate for inefficiencies in existing systems as well as to provide more comprehensive data about the weaving section being monitored. We have used a vision sensor as our input. The rich information provided by vision sensors is essential for extracting information that may cover several lanes of traffic. The information that our system provides includes (but is not limited to): (a) Extraction of vehicles and thus a count of vehicles, (b) Velocity of each vehicle in the weaving section, and (c) Direction of each vehicle (this is actually a trajectory versus time rather than a fixed direction, since vehicles may change direction while in a highway weaving section). The end-product of this research is a portable system that can gather data from various weaving sections. Experimental results indicate the potential of the approach.