Speed Indicator Device (SID)

Following concerns from residents and many, many months of efforts to
  complete the plan, East Coker now has a Speed Indicator Device (SID)
to remind road users to check their speed.  Periodically it will be
moved to one of four locations around the village and hopefully
  encourage all to consider if their speed is appropriate; it will be
set to the speed limit but this is not necessarily the safe speed.
  Regardless of whether it displays a speed and appropriate message, the
  unit records non-identifiable information regarding speed and time.
This data could be used to review the existing speed limits but it is
hoped that this is not required.  The locations in Higher Burton, on
  residential areas but positioning had to be approved by county
engineers according to roadside restrictions, as well as how the
  system best works.  There has obviously been a cost to establish this
  system but a scheme from Somerset and Avon Constabulary allows us to
  recover some of this cost as well as associated costs for
  installation.