bad rotation

[aloriza]

hello
im trying to make a game like rush(https://play.google.com/store/apps/details?id=com.ketchapp.rush&hl=en_US)

but i have problem in implementing curvy road
my problem is that road have bad rotation (look at image)
https://img.onl/oSsD
   


it happens some times not all time

and this is image of my game(image)
https://img.onl/TQb96w
   

and this is how i insert segments

public void start_game()
    {
       
        mDir = Vector3.forward;
        last_x = 0;
        last_y = 0;
        for (int i = 0; i < cp_count_to_start; i++)
        {
            Vector3 p = TrackSpline.ControlPointsList[TrackSpline.ControlPointCount - 1].transform.localPosition;
            Vector3 position = TrackSpline.transform.localToWorldMatrix.MultiplyPoint3x4(p + mDir * cp_step_size);

// UnityEngine.Random.value => it float between 0 and 1
//DTUtility.RandomSign() => its float between -1 and 1

            float rndX = UnityEngine.Random.value * CurvationX * DTUtility.RandomSign();
            float rndY = UnityEngine.Random.value * CurvationY * DTUtility.RandomSign();
         
            mDir = Quaternion.Euler(rndX, rndY, 0) * mDir;

            CurvySplineSegment newControlPoint = TrackSpline.InsertAfter(null, position, true);

        }
        TrackSpline.Refresh();

        for (int i = 8; i < TrackSpline.ControlPointsList.Count; i++)
        {
            enemy g = Instantiate(enemy_prefab, TrackSpline.ControlPointsList[i].transform.position, Quaternion.identity).GetComponent<enemy>();
            g.gameObject.transform.rotation = Quaternion.LookRotation(TrackSpline.GetTangent(TrackSpline.ControlPointsList[i].TF));
            enemys.Add(g.gameObject);
        }
        Controller.Speed = 100;

        Controller.Play();
    }

  public void Track_OnControlPointReached(CurvySplineMoveEventArgs e)
    {
        if (e.ControlPoint.Distance > 10 * cp_step_size)
        {
            tranfer_to_end(enemys[0]);
            GameObject g = enemys[0];
            enemys.RemoveAt(0);
            enemys.Add(g);
        }
    }

public void tranfer_to_end(GameObject g)
    {

        float pos = Controller.AbsolutePosition;
        pos -= TrackSpline.ControlPointsList[0].Length;
        TrackSpline.Delete(TrackSpline.ControlPointsList[0], true);
        Vector3 p = TrackSpline.ControlPointsList[TrackSpline.ControlPointCount - 1].transform.localPosition;
        Vector3 position = TrackSpline.transform.localToWorldMatrix.MultiplyPoint3x4(p + mDir * cp_step_size);

        float rndX = UnityEngine.Random.value * CurvationX * DTUtility.RandomSign();
        float rndY = UnityEngine.Random.value * CurvationY * DTUtility.RandomSign();
   
        mDir = Quaternion.Euler(rndX, rndY, 0) * mDir;

        CurvySplineSegment newControlPoint = TrackSpline.InsertAfter(null, position, true);
        TrackSpline.Refresh();
        Controller.AbsolutePosition = pos;


        g.transform.position = newControlPoint.transform.position;
        g.transform.rotation = Quaternion.LookRotation(TrackSpline.GetTangentFast(newControlPoint.TF));

    }

PLZ HELP