Use of SCATS MF to Calibrate SIDRA Saturation Flow

Abstract

This document presents a discussion on the use of the Maximum Flow values recorded in the SCATS traffic control system (SCATS MF) for calibrating Saturation Flow in SIDRA models of signalised intersections. While the concept of SCATS MF is similar to Saturation Flow, there are significant differences in how they are measured and applied. It is shown that valid values of SCATS MF are not available for many lanes, and where they are available, there are serious problems in translating SCATS MF to a reliable Saturation Flow value. Consequently, it is recommended that SCATS MF should not be used to calibrate SIDRA models. Instead, standard values of Basic Saturation Flow should be used, and models should be calibrated and validated against observed traffic performance measures.