Integrating Outcome Oriented Performance Measures into Traffic Signal Operations Business Processes

Deployment of improvements in signal systems are often constrained by a variety of issues. Some of these are technical, particularly the dependency of systems on the proper function of many different components. Other issues are institutional. This paper presents a view of the technical components based on the Open Systems Interconnection model that is tailored to specific aspects of signal systems, and discusses the business processes of signal systems deployment from a systems engineering perspective, as a framework for understanding how performance measures can be introduced as a means of connecting specific objectives with the appropriate use cases and audiences. An example is presented for the application of detector error checking from the perspective of a system built from the "bottom up" rather than the "top down".

I. Introduction

A recent study on the current state of the practice in traffic signal operation noted that [1], “the industry often promises what it cannot deliver, and then fails to deliver what it could, with better commitment and resources.” The Traffic Signal Report Card [2] has consistently yielded overall low scores for the industry. While exceptions exist, many agencies schedule improvements on arbitrary timelines, and they receive no operational feedback other than citizen complaint calls. The only available quantitative data are input-oriented measures of expended effort (such as the amount of money or personnel hours used). These do not directly show the outcomes of that effort—how the system is actually performing.