1. The residents should not be disturbed and a safe area is supposed to keep a distance from the residential buildings .For each side ,the width is 6-8 meters for the safety.
2. The location can neither be slop or steep slop ,nor too close to the ground. And the place where pavement or sidewalk for the blind is also forbidden. As well, the path for fire exit can not be influenced .
3. The design is supposed to be reasonable , the time for walking is 8-10 minutes.
4. maintenance: Once broken, the boards should be fixed at once .And the residents should take care to the malicious damage.