... day and night,attack the attention of the drivers to decelerate succesfully.5 Widely used,one of the newest ... the surface of asphalt roads and concrete roads.2) To improve life span ,the road must be smooth.After ... the special adhesive,put the bottom of the bump to the surface of the road 3) For A type ... ateel bar or PVC pipe to link them up from the middle holes in order to strengthen the power of force ...