private Vector tireCollisionWithMap(Vector pos, Vector lastPos)
        {
            int    ticks = 5;
            Vector spd   = (pos - lastPos) / (double)ticks;

            for (int i = 0; i < ticks; i++)
            {
                pos += spd;

                CollisionCircle      collisionTire = new CollisionCircle(pos, game.TireRadius);
                List <CollisionInfo> collisions    = CollisionDetector.CollisionsWithMap(collisionTire);

                if (!collisions.HasCollision())
                {
                    continue;
                }

                return(collisions.AverageNormalObj1());
            }

            return(null);
        }