- This project focuses on modeling protected and permitted left-turn operations at signalized intersection approaches, an area that has been identified as high-priority research by the FHWA NGSIM program. The project will use high resolution vehicle trajectory and signal timing datasets from California and Georgia to develop improved understanding of the left-turn operations at signalized intersections. The project will provide better understanding of the left-turn phenomena by identifying and documenting the microscopic characteristics of left-turn operational parameters both at the beginning and end of green. The project tasks also include a validation of macroscopic models used to estimate capacity and delay for left-turn traffic. The project output will be documented in six technical memoranda and a final report.