Incorporating Advanced Signal Control Systems into an Archived Data User Service Program

About the report:

The deployment of Intelligent Transportation Systems (ITS) that incorporate some type of data collection or traffic surveillance capabilities has been rapidly increasing over the past decade. More recently it has been recognized that these data collection systems can be used as additional sources of mobility data, augmenting traditional data sources such as relatively sparsely distributed permanent count stations and supplementary 48-hour volume counts. Most of the research conducted to date has focused on data archiving systems that have freeway system data collection equipment as their primary data source. However, little is known about the feasibility of using advanced signal control systems (ASCSs) as sources of mobility data. A possible cause for the relative inattention to the use of advanced signal system equipment is that using an intersection as a source for road segment volume counts is contrary to conventional traffic data collection principles, which stipulate that road segment volume counts be taken outside the influence area of intersections. The purpose of this research was to determine if data collected from an advanced arterial signal control system could be used to generate information that would be useful for transportation engineering analyses other than signal optimization and control. This research also looked at some of the technical challenges and limitations to using data collected by an arterial signal control system and presents an analysis of the validity of the data. The premise investigated is that data from signal control system surveillance equipment can be used to calculate daily volume counts for a roadway segment. This premise was tested by screening and aggregating data from signal system data collection equipment and comparing it with data from traffic monitoring equipment located in close proximity to the intersections being analyzed. The results of this research support the conclusion that reasonable volume estimates can be generated from system detectors located upstream of the intersection stop bars if the system detectors are deployed on all major approach through lanes. This research also demonstrated that the utility of ITS data requires more than simply the deployment of ASCS or other ITS data collection equipment. In order for an ITS archived data management system to be successfully implemented, the data product needs of the end users must be considered in the design and deployment of the traffic monitoring and control system, as well as the data management system.

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