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Kent 4 star Council

Interactive signs

We use several types of interactive sign on Kent's roads. These signs help us to increase road safety.

What is an interactive sign?

There are now several types of interactive sign:

  • Speed signs - to alert drivers to the speed limit
  • Warning signs - to warn of bends or junctions with poor crash records
  • Speed indication device - to tell drivers their actual speed, as part of the SpeedWatch initiative

Put simply, an interactive sign is a sign that reacts to the behaviour of drivers. If a vehicle is moving faster than the speed limit, the sign will be activated.

Speed signs

The interactive speed sign is used to tell drivers that they have not reduced their speed after entering a lower speed limit.

Signs are placed 100 to 250 metres after the start of a lower speed limit. If a vehicle is travelling above the speed limit, a radar beam triggers the sign. When this happens, the speed limit is illuminated on the sign and flashing amber lights come on above and below that sign. The sign remains illuminated for four seconds.

We have placed roughly 80 signs around the county so far. A further 60 sites have already been chosen and are waiting to have signs put in place.

We fund the placement of 10 interactive signs every year. The average cost of these signs is about £5,000.

Can the council put these signs anywhere?

No. We have a policy for the use of interactive signs; they can only be used in the following places:

  • The sign should be installed between 100m and 250m from the start of the lower speed limit
  • The road at that point needs to be straight so that the radar beam can work
  • There should be no significant vegetation that would block the visibility of the sign or the radar beam
  • There should be no existing natural or engineered feature close to the intended sign that already acts as a speed-reducing feature
  • Wherever possible the sign should not be close to residential properties or be directly in line with bedroom windows
  • The sign is some 900mm wide so sufficient footway or verge width is necessary, plus a minimum of 400mm to ensure that the sign is not hit by passing vehicles

Warning signs

These are the same as existing road signs, except that they light up in the same way as interactive speed signs. In a limited number of cases, the words 'slow down' can be added to appear in the sign.

They are used at sites, such as bends and road junctions, where there is a specific crash problem. These will be sites where traditional casualty reduction measures have failed to reduce the number of accidents caused by speeding.

Speed Indication Device (SID)

These signs show the actual speed of the driver. They have three specific uses:

  • At roadworks to encourage drivers to slow down
  • As a temporary measure either as a trailer mounted sign or attached to a lamp column
  • As part of a Speed Watch initiative. What is Speed Watch?

Who can request that an interactive sign be put in place?

Parish councils can fully fund a sign that we will put in place, if the above criteria are met.

Members of the public who think that an interactive sign would be useful on a particular stretch of road should talk to their parish council.

The cost of putting in place and maintaining the signs means that we can place only a small number of signs each year, unless outside funding is available.

Copyright Kent County Council 2008