Evaluation of Tesla Dashcam Video System for Speed Determination Via Reverse Projection Photogrammetry

Recent Tesla models contain four integrated onboard cameras that serve the Autopilot and Self-Driving Capabilities of the vehicle and act as a dashcam by recording footage to a local USB drive. The purpose of this study is to analyze the footage recorded by the integrated cameras and determine its suitability for speed determinations of both the host vehicle and surrounding vehicles through photogrammetry analyses. The front and rear cameras of the test vehicle (2019 Tesla Model 3) were calibrated for focal length and lens distortion characteristics. Two types of tests were performed to determine host vehicle speed: constant-speed and acceleration. Several frames from each test were analyzed. The distance between camera locations was used to gather vehicle speed through a time distance analysis. These speeds were compared to those gathered via the onboard GPS instrumentation. Two additional types of tests were performed to determine surrounding vehicle speeds: a vehicle approaching from the rear and an offset vehicle approaching from the front. For both tests, the Tesla was stationary. Several frames from each test were analyzed via reverse projection, using a point cloud of the approaching vehicles. The speeds obtained through photogrammetry were compared to GPS instrumentation onboard the approaching vehicle. The mean difference between photogrammetry and GPS instrumentation ranged between 0.38 and 0.72 mph across all tests.