- What are vehicle activated signs?
- Speed management plans
- When might we use VAS?
- How to submit a VAS request
- VAS site assessment
- Funding and installation
- Post-installation monitoring
What are vehicle activated signs?
Vehicle activated signs (VAS) are a useful and cost-effective road safety intervention. They light up to warn drivers of hazards or to remind them of the speed limit if they are approaching too fast.
As of 2023, there are approximately 650 VAS in Surrey including on the approach to nearly all our speed cameras. Monitoring shows VAS helps drivers keep to the speed limit and this effect is on-going.
The VAS used in Surrey are programmed to light up when a car travels faster than a set threshold. So, they only display to the drivers who need them most. We do not use the "smiley face/sad face" or the "your speed" type of VAS because they light up for every driver, eventually becoming part of the background and likely to be ignored.
Speed management plans
We work with Surrey police on a speed management plan system with local plans for each of our districts and boroughs.
If there are concerns about vehicle speeds in a local area, we take measurements to understand the issue. We also use data on speeding and accidents to work out which sites are the highest priority.
If we do not already have speed data for a site, we gather it via a speed detection radar device fixed to street lighting. With a rolling programme of speed surveys, data for one week is generally recorded within a month of any request.
For the highest priority sites, we may use speed cameras, traffic calming and police enforcement. In other areas, VAS and other measures can help.
When might we use VAS?
We may invest in VAS if the 85th percentile speed (the speed above which the fastest 15% of drivers are travelling) is greater than that shown in the table below. This threshold is also the lowest speed trigger that will light up the sign so only the fastest drivers receive a warning from the VAS.
Threshold for considering VAS and illumination trigger point (85th percentile speed)
|20 mph||24 mph|
|30 mph||33 mph|
|40 mph||44 mph|
|50 mph||55 mph|
|60 mph||66 mph|
How to submit a VAS request
If you have concerns about speeding in your local area, you can submit a VAS request.
VAS site assessment
We visit each proposed VAS site to see if it is suitable. This takes around two months from the date of the request. We consider the following when deciding if VAS can be used:
- Is there enough room at the side of the road to position the VAS so it does not cause an obstruction?
- Can the VAS be positioned so it is not too close to, or overlooking, any dwellings or businesses to avoid intrusion?
- What size of sign would be best for the nature of the road? Smaller signs can be used on lower speed roads but larger signs are necessary on higher speed roads.
- Is there a suitable mains power source? Smaller, lighter VAS can be mounted on existing street lights but larger VAS need their own electrical post. We do not use solar powered VAS as experience has shown their batteries can run out of power daily and they degrade over time.
- Is there any foliage that will cause an obstruction to the VAS?
- Is there a good line of sight to the oncoming traffic so the VAS can detect vehicles?
- Will drivers be able to see the VAS light up at the right time?
Funding and installation
If a site is suitable, VAS funding options are then considered. Our road safety budget supports VAS at high priority sites. Other sources of VAS funding may include local Member allocations, parish and town council, and third party or developer funding.
Once funding is confirmed, we get quotes for electrical works and the supply and installation of the right VAS for the site. Quotes are usually returned within a month, reviewed and an order placed. VAS installations are programmed in packages or as part of VAS maintenance. This is cost-effective because works are programmed when road space is available to minimise congestion on the roads. Installation can take four to five months from ordering.
We inspect new VAS within a month of them going live. Speed surveys are usually carried out within six months to check the VAS has helped to reduce speeds and the threshold speed is set at the right level.
|VAS request received||Start date|
Speed survey (if not already available)
One to two months
Quote for electrical works and VAS sourcing, with review and acceptance
Four to six months
One to two months
Within six months of installation