Barriers may comprise of separate portable post and plank systems, gate frames linked together or semi permanent constructions built to enclose the site. Barrier planks are required to carry out three main functions:

• As a TRAFFIC BARRIER - When a traffic lane is closed for works to take place, the regulations require this to be done with a retroreflective red and white barrier plank placed accross the lane.
  
  
• As a PEDESTRIAN BARRIER - Pedestrians must be separated from the works by barriers which are conspicuous and mounted as part of a portable fencing system. Pedestrian barrier planks may be of several different contrasting colours; yellow, white or orange colours are best detected by partially sighted people, but red and white is one pof the acceptable combinations
  
  
• As a TAPPING RAIL - For blind and partially sighted people. Tapping rails are placed as the bottom rail in a pedestrian fencing system. A red and white barrier plank may be used