Develop and demonstrate methods by which a vehicle safety communications system on a heavy vehicle tractor can automatically determine the geometric parameters of the trailer being towed. This information is required to assemble a Basic Safety Message (BSM) that conveys the dynamically changing position of an articulated tractor- trailer combination vehicle to surrounding vehicles. A review of existing object-detection technologies and the means to extract the trailer parameters from these technologies was conducted. The classes of trailers with highest market penetration were identified and used in the development process of the trailer detection system so as to maximize the applicability to a majority of trailers on the road today. Using the required trailer descriptive parameters defined in the previous study, accuracy requirements were developed. These were derived based on the light vehicle requirements for Vehicle-to-Vehicle (V2V) communication specified in SAE J2945/1. Trailer- identification related data were collected using LiDAR (2D and 3D), radar, camera (monocular, stereo and thermal), and ultrasonic sensors. Subsequent evaluation of the data resulted in the selection of a subset of these technologies for development into a prototype system. The final system technologies included:​ camera (stereo and monocular), LiDAR (2D and 3D), and ultrasonic. The 3D LiDAR based measurement system developed was able to accurately detect and measure the trailer parameters for box and tanker style trailers which accounts for nearly 90 percent of the trailers in use on roadways in the United States. Also demonstrated were trailer identification solutions based on other technologies. The camera-based solution provided a less robust means than the 3D LiDAR while the ultrasonic and 2D LiDAR was found to be applicable for fixed axle trailers only. The system designs did not require any special trailer markings or input from the driver. In addition, a simpler alternative solution for some fleet applications was developed that utilized markings (AprilTags) placed on the trailer for identification. This research demonstrated that there were methods to determine trailer parameters automatically for use in vehicle safety communications systems on articulated heavy vehicles. The system developed in this study allowed for a sufficiently accurate representation of the position of tractor-trailers during turning maneuvers in the BSM. This is important for effective implementation of safety applications based on vehicle safety communications.