Also, aviation radars are built to reject signals from objects that are stationary relative to the ground so they aren't swamped by signals from the ground itse

Also, aviation radars are built to reject signals from objects that are stationary relative to the ground so they aren't swamped by signals from the ground itself ("ground clutter"). Does Tesla's radar do something similar? If so it'll have no trouble picking up other cars traveling along the road but won't be able to see a stationary truck.