Forward Collesion Warning System

Hi everybody,

I have some questions about FCW system:

1- The FCW system can be camera based and radar based. How does the camara based work in fog?

2- we know that recognition systems can be based on either Radar or Lidar. But the FCW is developed with Radar? why? Why it's not on Lidar based?

3- When can we use Lidar and when Radar?


Regards,
Parisa