 In addition to their general road policing duties, they assist with various operations aimed at improving road safety and are also at the forefront in tackling vehicle crime and the criminal use of the roads network.They are also available to back up other units, as they are constantly roaming an area as part of their high visibility patrolling work.A sub-unit of the RPU is the Collision Investigation Unit (CIU) or Forensic Collision Investigation and Reconstruction Unit (FCIRU), which exists to manage the follow-up investigations into all fatal and very serious collisions.