The surface pedestrian crossing model includes requirements and standards in terms of visibility, drainage, lighting, pavement, road signs, traffic timing and other factors. For instance, for traffic crossings, there is a requirement that the green crossing signal be open for sufficient time to allow the whole track to be crossed at a speed of 0.4 m/s. To facilitate the crossing of the visually impaired, the model requires traffic lights to be equipped with mechanisms that emit sounds and vibrate.