surface. In these cases, the roller must be turned around to allow the tiller wheel to compact the material partially so the drive wheel can then proceed over it. tandems, static-weight or vibratory, while the hot mat is still warm enough for removal of roller marks. ROLLER  SAFETY Intermediate Rolling Intermediate rolling should closely follow break- down rolling, while the asphalt mix is still well above the minimum temperature of 185 degrees at which densification  can  be  achieved.  Pneumatic-tired  or vibratory rollers may be used for intermediate rolling. Pneumatic-tired  rollers  have  several  advantages: 1. They provide a more uniform degree of com- paction  than  steel-wheeled  rollers. 2.  They  improve  the  seal  near  the  surface  by kneading the  material  closer  together. 3. They orient the aggregate particles for greatest stability,  as  high  ground  pressure  truck  tires  do  after using the asphalt surface for some time. Tire contact pressures should be as high as possible without causing displacement of the mix that cannot he remedied in the final rolling. Pneumatic-tired rolling should be continuous after breakdown rolling until all of the hot mix has been thoroughly compacted. At least three coverages should be  made. NOTE: Turning  of  pneumatic-tired  rollers  on  the hot mix should not be permitted unless it does not cause undue  displacement. Vibratory rollers (of proper static weight, vibration frequency,  and  amplitude)  are  used  to  provide  required densities  with  fewer  coverages  than  static-weight tandem  or  pneumatic-tired  rollers  (or  combinations  of the  two). Regardless of the type of roller used, the rolling pattern should be developed in the same manner as for breakdown rolling. This pattern should be continued until  the  desired  compaction  is  obtained. Finish Rolling Finish rolling is done solely for the improvement of the  surface.  It  should  be  accomplished  with  steel-wheel Many of the safety precautions previously listed for graders, scrapers, and dozers also apply to roller opera- tions.  Additional  safety  precautions  are  as  follows: . Never perform roller operations alone. Always have a safety person in the area of the rolling operation. l Only operate the roller at speeds at which the machine can be kept under control at all times. . Always wear a scat belt when rolling, as well as other required personal protective equipment, such as steel toe safety shoes and hard hats. l Operate the roller from the sitting position, never from  a  standing  position. . Use the safety handrails when mounting or dis- mounting a roller. Do not grab the transmission control levers, as this might cause the roller to make a sudden movement. l If the roller ignition starts in any transmission position  besides  neutral,  this  machine  should  be hardcarded and repaired before further usage. . Use caution and make sure the area is clear of personnel,  tools,  and  vehicles  when  performing  forward and  reverse  rolling  operations. . A roller is easier to overturn than most equip- ment. Rolling on a side slope should always be done at right angles or diagonally, rather than parallel to the s l o p e . . Steer carefully when rolling a shoulder to avoid capsizing into the ditch, and never bring a roller near the edge of a cut. c Use extreme care when loading steel-wheeled rollers  on  tractor-trailers  during  periods  of  inclement weather, The wet deck of the trailer can cause a steel- wheel  roller  to  slip  during  loading  and  unloading operations. 11-29