Hybrid Model for Estimating Permitted Left-Turn Saturation Flow Rate

Abstract

This study explored the integration of analytical formulations with simulation results for estimating the complex permitted saturation flow rate. The proposed hybrid model captured most tractable interactions between the permitted flow rate and the opposing flows with the widely used formulation by Drew, which serves as one of the primary explanatory variables. To further consider the complex interactions between the permitted flow rate and all other associated factors, which often are not consistent with the assumptions used in analytical derivations, this study modeled the intractable relations as multiplicative adjustment terms and estimated their parameters with log-linear regression. Such a hybrid formulation offers the flexibility to incorporate various additional critical factors on the permitted flow rate, including the variation of driving behavior, the number of opposing lanes, the progression quality, and the heavy vehicle percentage. The preliminary tests with extensive simulation experiments have shown very promising results.

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