Methods, systems, and devices are provided for calibrating a light ranging system and using the system to track environmental objects. In embodiments, the approach involves installing light ranging devices, such as lidar devices, on the vehicle exterior. The light ranging system may be calibrated using a calibration device to scan the vehicle exterior and construct a three-dimensional model of the vehicle exterior comprising the positions of the installed light ranging devices on the vehicle exterior. The calibrated light ranging system may use the model in conjunction with ranging data collected by the installed light ranging devices to track objects in the environment. In this way, the light ranging system may detect a proximity of environmental objects and help a driver of the vehicle avoid potential collisions. The light ranging system may further measure the vehicle exterior and thereby detect changes to the vehicle exterior.