Unipart Dorman
A division of Unipart Logistics North America. The only choice in traffic calming and road safety products for municipalities everywhere. We cater specifically to highway safety engineers, schools, and emergency services in providing innovative independently proven safety standards unparalleled in the traffic calming industry.
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Why VATCS and Why not Speed feedback signs?
History of VATCS
VATCS are electronic LED road side signs which are directly targeted and proven to have an effect on lowering driver vehicle speeds. Signing with VATCS is a means of providing a simple effective message relating to conditions on the highway (presence of hazards, intersections or speed requirements) to specific drivers.
The signs use warning or regulatory diagrams from the MUTCD/OTM which are inverted and translated into pixilated LED display diagrams, the diagrams are enhanced by either having the wording ‘Slow Down' beneath or having flashing amber led lanterns in each corner or both.

The signs are importantly hazard specific and are targeted at only the motorist exceeding the threshold speed which is a key to their success. The sign will remain blank until a vehicle approaches (distance 70 to 100m) exceeding the pre-set speed threshold. The sign will then illuminate for a 3 to 4 second configurable period warning the driver to Slow Down.
Early work on VATCS started in the early 1980s , automatic signs were trialed providing drivers with information relating to either excessive speed or being to close to lead vehicle. The signs were initially constructed using a combination of neon and fluorescent back lit display methods and activated using inductive loops or infra red technology.
The latest generation of VATCS, combine High Intensity LED display technology with microwave radar speed detection technology. LEDS are selected on optical grading of uniformity, color and brightness with auto luminosity control and microwave detection has been developed to provide an accurate uniform reading of vehicle speeds to a tolerance of +/- 1Mph.
In 2002 The Transport Research Laboratory on behalf of the Road Safety Division of UK Department for Transport published ‘TRL548', a large scale evaluation study on the VATCS technology. The study was conducted over 3 year period on 60 No VATCS signs and provided the following strong independent endorsement of the product.
- A 4 MPH reduction of average speed in Speed Limit Zones.
- A 7 MPH reduction of average speed in Advance of Specific Road Hazards.
- A 4 MPH reduction of average speed in advance of Safety Camera Locations.
- A 1/3 reduction in expected accidents recorded over the 3 year period.
The unparalleled study lead to the VATCS being incorporated within the UK MUTCD manual with guidelines for deployment and best practice. VATCS are now common place tools being deployed by UK road safety strategists in their challenge to meet world leading targets for reducing speed related road fatalities by 2010.
Following TRL548 the UK department of transport accountable to the UK government introduced a road safety strategy which included three targets, by 2010 they want to achieve compared to the average for 1994-98.
- 40% reduction in the number of people killed or seriously injured in road accidents.
- 50% reduction in the number of children killed or seriously injured.
- 10% reduction in the slight casualty rate, expressed as the number of people slightly injured per 100 million vehicle miles.
In 2003 , 3508 people were killed in road accidents and , 33,707 were seriously injured. This is 22% below baseline – almost half way to the 40% target set for 2010. 171 children were killed in road accidents and , 3,929 were seriously injured. This is 40% below baseline – over three quarters of the way to the 50% target.
With the independent supporting evidence of the only internationally recognized large scale field study, TRL548 report. VATCS have started to make an impact into North America and the first full year case study form the City of Woodstock, on the technology has provided the first mid term evidence that the effects of the VATCS solution is being replicated in North America.
All VATCS are supplied as standard with data logging to allow clients to perform their own speed analysis and VATCS performance evaluation.
DV NA portfolio currently offers clients both VATCS and SFD traffic calming device options. DV NA strongly recommend that if clients are looking to a permanent installation with a long term objective of speed management then VATCS devices should be deployed at all times. With VATCS attaining driver respect for long term and statistics showing the best traffic calming results coming from an educated and reasonable approach to the driver ,VATCS are now being deployed in place of physical measures such as speed humps and are the leading choice in traffic calming display devices.
In the case of temporary rotational deployment or operation via timer at certain times of day in school zone application, then both VATCS and SFD devices can be considered for deployment . Some of the features that set VATCS apart from other traffic calming display devices are listed below:
Independent Track Record
VATCS are the only traffic calming display technology that have been large scale field tested to prove long term effectiveness with driver respect of the technology being maintained. See TRL548.
Targeted Message
VATCS are targeted at only the speeding motorist remaining blank at all other times. Speed feedback signs should be operated in this fashion as well but commonly some incorrectly provide a blanket message to all drivers of what speed they are travelling whether they are speeding or not. By having a fixed text portion of message SFD signs are visible at all times whether active or not.
Clarity of Message
In line with the core philosophy of a consistent road speed management strategy, VATCS utilize regulatory and warning diagrams that are all ready recognized in the MUTCD. Drivers are not informed what speed they are travelling, rather they are advised of posted speed limit and to Slow Down where excessive speed has been detected.
Speed feedback signs although covered in MUTCD can provide a controversial message especially in two approach lane scenarios and in worse case can encourage certain drivers to see how far they can make the sign read up to, therefore possibly exacerbating the existing problem. (See picture above )
Perception Reaction Time
VATCS use established warning and regulatory diagrams from the MUTCD which are automatically recognizable to the motorist, therefore perception , understanding and reaction times are lower and proven to be more effective.
Hazard Specific
VATCS are hazard specific, eg. If you have a sharp curve in the road that is causing road departure incidents, then the VATCS that would be used would incorporate the curve warning diagram, with slow down and Lanterns. The speed feedback signs only have the one message which is not universal.
Flexibility Drive To Conditions
An important feature of VATCS is that speed thresholds can be adjusted to be below normal posted if required. i.e. A curve may be more difficult to maneuver during winter months than summer, the display can be adjusted to a lower threshold speed to suit conditions. Getting drivers to drive to conditions is a very important factor in the majority of road accidents.
Portability
In recognizing Portability has advantages, VATCS are available in scaled down dual diagrams formats so that they can be rotated between speed zones. However batteries alone are not considered a reliable power source. Solar or AC power should be used at all times.
VATCS Technology … Facts
- 40% reduction in the number of people killed or seriously injured in road accidents.
- CASUALTY & SPEED REDUCTION POTENTIAL …TRL Transport Research Laboratory 3 year report provided figures of between 4 to 7mph reduction in average speeds where VATCS are deployed, with a 1/3 reduction in expected accident rates. In addition it was noted that the number of excessively high speeds recorded prior to install were significantly reduced.
- COMMUNITY REASSURANCE…VATCS provides community "reassurance". Reduction in excessive speed levels in neighbourhoods goes hand in hand with improving quality of life. “Getting community to buy in to the concept is half the battle”.
- LASTING EFFECT…
- VATCS are solutions for the long term . No significant diminution in performance independently recorded over 3 year period.
- POPULAR…are popular with residents (TRL research). Persuasive rather than enforcement. ‘Driver responsibility, given reasonable help, underlies much road safety policy.'
- COST EFFECTIVE...range typically $4,500 to 7,000.
- DRIVER ENVIRONMENT...No damaging effects to drivers vehicles that can be a common problem with speed humps, gateway structures etc...
- EMERGENCY VEHICLES...can pass by unhindered in emergency situations.
- SIMPLE DISCRETE INSTALLATION...Lightweight GRP or Aluminum housings, discrete single post mount.
- INTERACTIVE...drivers can immediately see that they are causing the sign to warn them, and it reacts when they slow down.
- DYNAMIC...Attention grabbing – high intensity LEDS. Focused display on drivers view, no light pollution effects on adjacent roads users or adjacent property.