Experimental Evaluation of the Stimuli-Induced Equilibrium Point Concept for Automatic Ramp Merging Systems

The concept of stimuli-induced equilibrium point (SIEP) has been recently introduced to characterize the psychological interaction of a ramp driver with its putative leader and follower on the expressway during a merging maneuver. It enables the computation of the reference target gap speed and position for the on-ramp merging vehicle based on current traffic conditions and ramp vehicle response. The SIEP has been shown to improve the performance of existing automatic ramp merging control strategies while increasing the level of safety during the merging maneuver. The performance and advantages of the SIEP-based approach have been assessed only through numerical simulations. In this paper, we conducted a comprehensive experimental evaluation of the performance and safety of this SIEP-based approach to ramp merging control using a lab-based test-bed. We employed a novel Pc metric, which is based on the concept of probability of collision, to perform a systematic validation of the SIEP safety. Such a metric serves as a standardized methodology to quantitatively compare the SIEP-based approach with those in this paper.