Because the wheels are round the ground is flat, the pi is also due to friction
Because the car is going to move forward, the wheels must be turned
We know that sliding to overcome the friction, and rolling is actually the moment to overcome the torque. In the actual case, the contact portion of the wheel and the ground is not just a point, the wheel will change in elasticity, so that the contact part is a surface, the ground support force multiplied by the length of the contact surface is to roll to overcome the torque, The wheel's thrust is multiplied by the radius of the wheel, that is, the active moment, the active torque overcomes the ground support torque, and the wheel rolls forward.
Should be flat for the ground
