Casted ray doesn't detect surrounding as an obstacle?

Hello,
I was working on this car game demo proj. I am trying to develop a collision avoidance systmem, I am able to avoid cubes and other things created as a gameobjects, but i’m not able to do the same for the surroundings in the track.
any suggestions?

Do objects in your surroundings have colliders attached? You should check collider parameters to be the same as in your successful attempts. Also, raycast function returns false when you cast from the sphere to outside.