Field Evaluation of V2I Connected Vehicle Deployment in Ada County, Idaho: Validating Communication Architecture and Control Technology Readiness

Abstract

The primary objective of this project was to conduct a field evaluation of a vehicle-to-infrastructure (V2I) connected vehicle traffic signal system deployment in Ada County, Idaho, focusing on validating the communication architecture and control technology readiness for broad implementation. To that end, the reliability of line-of-sight packet exchanges between roadside units (RSUs) and on-board units (OBUs) was extensively tested in the field as a function of the OBU speed and the distance between the OBUs and the RSUs. Two metrics were considered in assessing this V2I communication reliability, the received signal strength indicator (RSSI) and the packet delivery ratio (PDR). To be able to reliably assess the quality of OBU/RSU communication for OBU/RSU equipment from different vendors, the project focused on developing a vendor-independent reliability testing approach for V2I communications in connected vehicle traffic signal system applications. This was intended to provide an alternative to using the communication data reported by proprietary vendor-supplied interfaces. Our approach was based on building a rigorously tested translation model that uses measured RSSIs from any V2I communication equipment to predict the corresponding PDR values. The results were statistically analyzed and models that predict PDR values were developed. A case study to test and validate this new PDR prediction model was conducted at two intersections in Boise, Idaho. The developed prediction model will enable transportation system operators to test and validate the efficiency of connected vehicle RSU/OBU communications at signalized intersection approaches under different traffic conditions, independent of vendor-provided tools.