Passive Sensing Communication to Vehicles in Construction Work Zones Through Signage Coded on Pavement Surface

Construction work zones (CWZ) present safety challenges because of speeding, distracted driving, and improper lane changes. The objective of this research was to enhance CWZ communication and safety for vehicles through pavement signage coded on the road surface. First, an electromagnetic (EM) signature was applied to a pavement surface through a process of magnetizing epoxy-encapsulated chromium dioxide (CrO₂) particles. Next, a 3-axis magnetometer array was mounted on a cart to detect the passive EM signature strips and interpret the cart’s speed or upcoming lane maneuvers based on the collected EM signals. Field experiments were conducted in a parking lot with pavement-placed EM strips and a cart equipped with a magnetometer sensor array to demonstrate the CWZ concept. Test case#1 had EM signature strips at a 90° inclination and successfully determined the cart speed by dividing the fixed EM strip spacing by the time between peak signal pulses. Test case#2 with EM strips at 90° and 60° orientations validated the passive sensor system identification of speed and lane-merge action. Differences between the peak response times from magnetometer sensors on the cart’s left, center, and right determined the direction of the upcoming lane merge. The introduction of 3-axis magnetometers improved the data available to calculate and verify speed and maneuver actions by having redundant sensors containing similar interpretation of speed or maneuver action. The study confirmed that pavement signage coded roads and magnetometer array on a vehicle can effectively predict speeds and upcoming maneuvering actions, which should improve overall driver safety and mobility through CWZs.