The only thing it needs to do is to build a 3D model and ensure the car's speed isn't faster than anything in front of it. It doesn't need to know whether it's

The only thing it needs to do is to build a 3D model and ensure the car's speed isn't faster than anything in front of it. It doesn't need to know whether it's a trailer or a bird or Superman. Just that if the relative speed is negative, then adapt the car's speed. Maybe ignore small things like insects or birds, if you're that inclined. There is Gaussian splatting now. That seems fast enough for real-time, and would provide all that you need for this. If enough Gaussians are about to hit the windshield, slow the f* down.