  The introduction of light emitting diodes (LED) in automotive exterior
lighting systems provides opportunities to develop viable alternatives to
conventional communication and sensing technologies. Most of the advanced
driver-assist and autonomous vehicle technologies are based on Radio Detection
and Ranging (RADAR) or Light Detection and Ranging (LiDAR) systems that use
radio frequency or laser signals, respectively. While reliable and real-time
information on vehicle speeds is critical for traffic operations management and
autonomous vehicles safety, RADAR or LiDAR systems have some deficiencies
especially in curved road scenarios where the incidence angle is rapidly
varying. In this paper, we propose a novel speed estimation system so-called
the Visible Light Detection and Ranging (ViLDAR) that builds upon sensing
visible light variation of the vehicle's headlamp. We determine the accuracy of
the proposed speed estimator in straight and curved road scenarios. We further
present how the algorithm design parameters and the channel noise level affect
the speed estimation accuracy. For wide incidence angles, the simulation
results show that the ViLDAR outperforms RADAR/LiDAR systems in both straight
and curved road scenarios. A provisional patent (US#62/541,913) has been
obtained for this work.
