Speed Indication Devices
What is a Speed Indication Device (SID)?
A SID is a luminous sign which displays and records the speed of each vehicle that passes. They are designed to encourage drivers to reduce their speed and help to protect road users and pedestrians. SIDs can be used in various speed limits in both urban and rural areas. They do not record speeding offences but may be used to inform additional casualty reduction measures such as speed enforcement or to encourage Community Speed Watch schemes.

What information does the SID collect?
SIDs collect the speed, date and time for each vehicle that
passes. This information can be summarised and the results reported
back to the local community. The information may also be used to
identify speeding issues that require further action.
Two different types of SID are used in Staffordshire:
Post mounted SID
These SIDs are mounted on temporary posts or lamp columns and are
in place for 3 weeks. The locations used are based on collision
information and local concerns. The SID displays speeds at or below
the speed limit in green, and speeds above the speed limit in red.
Very high speeds are not displayed but are still recorded.
Trailer mounted SID
This SID is mounted on a trailer to allow flexible short term
deployment to problem areas or to support community events. The
locations used are based on collision information or requests from
local communities. The display shows the speed of approaching
vehicles along with a happy or a sad face depending on whether the
vehicle is within the speed limit.
