Vehicle system lidar fog detection and compensation

Techniques for detecting and determining a density for a non-impeding object based on correlation between radar and lidar returns are described herein. The techniques provide for receiving lidar data and radar data from a vehicle system operating in an environment. Portions of the lidar data and radar data are determined based on being associated with moving objects in the environment. The portions are then correlated to determine a similarity between the radar and lidar data. The similarity may then be used to determine an indication and density of the non-impeding object in the environment and cause the vehicle to operate within the environment accordingly.