When I try to move my character-object (car on road) by physics (rigidbody.velocity) it vibrates a little when mooving! And because my camera is following this object, it is vibrating too and everything became stuttering on screen! Where is my problem? I try everything to fix it!

Thank you, I found, that my variable CurrentSpeed (from code below) was changing in Update() too, so, moving it to FixedUpdate() solve the problem! Thx!