Longitudinal Performance Measures for Assessing Agency-Wide Signal Management Objectives

摘要

A fundamental concept of system engineering is defining operating objectives. Once those aredefined, it is important to select the appropriate strategy and performance measure for assessinghow well the system is working. This paper identifies two operating objectives that are broadlyshared by many agencies: i) Reliable communication to traffic signal infrastructure and ii) Goodallocation of green times. The first objective is oriented at asset management, and the second atoperational efficiency. However, there are substantial synergies between both objectives. Thispaper proposes performance measures for evaluating whether those objectives are being met.The quality of communication is evaluated by examining connectivity and data completenessbased on an open standard telecommunications model. Opportunities to improve green timeallocation are detected by identifying operating patterns where some phases routinely force offand other phases gap out in the same cycle. The performance measures are presented in an easyto-understand visual format that we believe is useful for practitioners. One of the outcomes ofthis system engineering approach is the realization that many of our objectives can be achievedwith a high-latency, low-bandwidth communication infrastructure, provided the appropriateprocessing techniques and performance measures are clearly articulated. The paper explains thearchitecture and performance measures in the context of a deployment of 122 intersectionsgeographically distributed throughout the state of Indiana with data collected over a two-and-ahalfmonth period using a variety of communication infrastructure ranging from commercialcellular data to agency-owned fiber.