/// <summary>
        /// Remove intersection from the world
        /// </summary>
        public void RemoveIntersection(FourWayIntersection intersection)
        {
            // Remove any cars that may be on the intersection
            foreach (List <Lane> ll in intersection.CurrentTrafficLightState.activeLanes.Values)
            {
                foreach (Lane l in ll)
                {
                    while (l.Vehicles.Count > 0)
                    {
                        RemoveCar(l.Vehicles[0]);
                    }
                }
            }

            // Remove any roads connected to intersection
            while (intersection.Roads.Count > 0)
            {
                RemoveRoad(intersection.Roads[0]);
            }
            Intersections.Remove(intersection);
        }