Stochastic Calibration of Automated Vehicle Car-Following Control: An Approximate Bayesian Computation Approach

This paper presents a stochastic calibration method based on Approximate Bayesian Computation (ABC). This method is applied to calibrate two car-following control models: linear control and model predictive control (MPC). The method is likelihood-function-free, where the likelihood function is replaced by simulation to approximate the posterior distribution of model parameters. This structure affords flexibility to calibrate posterior joint distributions of complex models, even those without analytical closed forms such as MPC. Two experiments were conducted to evaluate how well the proposed method reproduces: (i) marginal and joint distributions of model parameters, using synthetic data and (ii) vehicle trajectories (acceleration, speed, and position), using field data involving two commercial adaptive cruise control (ACC) systems. The results showed that the ABC method can reproduce marginal and joint distributions reasonably well for the linear controller as well as the non-analytical MPC-based controller, which was previously infeasible. The method can also robustly characterize the commercial ACC behavior at the trajectory level, which suggests that the simple linear controller better describes their behavior.

I. Introduction

Automated vehicles (AVs) are garnering attention for their potential to transform transportation systems. Among many potential benefits, AVs can presumably improve traffic efficiency, stability, and safety through advanced sensing and communication [1], [2]. AV car-following (CF) control, known as adaptive cruise control (ACC) is one of the earliest and most well-known automation features available in the market, enabling level 1 automation as defined by the Society of Automotive Engineers (SAE) [3]. ACC algorithms have been shown to behave differently from human driving behaviors. This has sparked a great deal of interest to better understand the behavior of vehicles with ACC and its traffic impacts through field experiments [4], [5], [6].