Cars are typically specced to handle 75kg (~165lb) of baggage on roof rack without breaking a sweat. Think carrying skies + personal gear on a trip across Europe. And if you are concerned about momentum, please note it's common to carry two bicycles on a roof rack; with speeds of 100km/h+ they generate substantial forces due to drag and in case of cornering.

I doubt the whole camera+lidar roof package is anywhere near close; best guess around 10kg (~22lb)