PhD Final Defense – Apidej Sakulneya

Enhancing Vehicle Maneuvers and Safety Through Pavement-Encoded Signage

Advisor: Professor Jeffery Roesler

Abstract

Human error is the major factor contributing to vehicle crashes and fatalities and even with the introduction of automated driving systems (ADS), roadway fatalities have not decreased. Furthermore, the risk of fatal crashes increases on rural roads, under adverse weather conditions, and in construction work zones (CWZs). The objective of this research was to develop a passive pavement-encoded signage system that supports vehicle-to-infrastructure (V2I) communication and enhances the safety of road users and road workers under a wide spectrum of roadway operations and conditions. The fabricated system applied a programmable magnetic strip to the pavement surface, which enabled vehicle-mounted magnetometers to detect and communicate roadway information and guidance without relying solely on the visual perception of the driver and vehicle.

A combination of lab and field experiments was conducted to evaluate detectability, interpretability, and repeatability accuracy of pavement-encoded signage across different pavement types, speeds, and weather conditions. First, the programmable pavement-encoded signage was laid out in a parking lot to communicate speed and lane-merge warnings in a CWZ and was verified using a pedestrian cart equipped with a 3-axis magnetometer sensor array at low-speed conditions. Next, the pavement-encoded signage and sensor system was integrated into an ADS vehicle to further validate the reliability and accuracy of this system under various maneuvers and speeds up to 55 mph. Pavement-encoded signages, including CWZ warnings, lane-keeping, and intersection warnings, were developed and validated in both a closed-loop test area and on a tangent and horizontal-curve section of a rural roadway under normal and adverse weather conditions. With improved signal processing, V2I communication through the pavement-encoded signage system achieved a detection rate exceeding 95%, a mean lateral-position error of 1.0 inch, and speed estimation within 0.7 mph. This research has demonstrated that pavement-encoded signage can serve as a viable and complementary infrastructure-based V2I communication layer to improve roadway safety under various operations and conditions.