unity - Car driving through walls with transform.Translate()

I need help with a script for a very simple car that uses transform.Translate:

public class car1 : MonoBehaviour {

    public PauseMenu pause;
    [Space]
    public Car_Script car_s;
    public float speed;

    public GameObject car;

    void FixedUpdate()
    {

        if (car_s.InCar == true)
        {
            if(pause.isPaused == false)
            {
                if (Input.GetKey(KeyCode.W))

                {
                    car.transform.Translate(Vector3.forward * Time.deltaTime * speed);

                    if (Input.GetKey(KeyCode.A))
                    {
                        if (speed <= 0)
                        {
                        }
                        else
                        {

                            if (speed > 0F && speed <= 50F)
                            {
                                car.transform.Rotate(Vector3.down, 2F);
                            }
                            else if (speed > 50F && speed < 90F)
                            {
                                car.transform.Rotate(Vector3.down, 1.3F);
                            }
                            else if (speed > 90F)
                            {

                                car.transform.Rotate(Vector3.down, 0.9F);
                            }

                        }
                    }
                    if (Input.GetKey(KeyCode.D))
                    {
                        if (speed <= 0)
                        {
                        }

                        else
                        {
                            if (speed > 0F && speed <= 50F)
                            {
                                car.transform.Rotate(Vector3.up, 2F);
                            }
                            else if (speed > 50F && speed < 90F)
                            {
                                car.transform.Rotate(Vector3.up, 1.3F);
                            }

                            else if (speed > 90F)
                            {
                                car.transform.Rotate(Vector3.up, 0.9F);
                            }

                        }
                    }
                }
            }
        }

    }
}

Whenever I drive the car it immediately goes through walls.

I have colliders on everything. The car has mesh colliders set to convex.

I've searched around quite a bit for answers and it seems that a common one is using rigid bodies. But whenever I even put a rigid body on the car, it flies out into the sky.