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Sway's Flashing SLR Project

What is a flashing SLR?

A Vehicle Activated flashing Speed Limit Reminder sign is one that displays the speed limit along with an appropriate message when it detects that an approaching vehicle is exceeding the speed limit. It differs from a Speed Indicator Display (SID) in that the latter will show the vehicle's speed, whereas the SLR actively reminds the driver of the speed limit. An unattended SID can often act as a challenge to some drivers who may attempt to discover just how high it goes. An SLR does not.

An example of a Speed Limit Reminder (SLR)
flashing SLR  

An example of a Speed Indicator Display (SID)
SID Dec 2015

Why does Sway need an SLR?

Since April 2014, Sway Community SpeedWatch (CSW) have been monitoring the speeds of vehicles on roads in Sway Parish that were identified as potentially having a speeding problem. Since July of that year, detailed statistics have been collected from the SID used by SpeedWatch. These statistics show the speed of every vehicle that went past (a total of nearly 62,000 as of November 2017). From these, we have been able to determine the number of people who exceed different speed thresholds ie around 26,700 exceed 30mph, 10,700 exceed 35mph, 2,200 exceed 40mph and so on. Since we also know the total number of vehicles that have passed (62,000), we know the percentage of those who exceed these thresholds. Our CSW webpage contains a number of statistics along with detailed reports going back to early 2016.

These statistics show that overall, 43% of motorists speed, and 40% of those that speed, do so at over the police enforcement threshold. Some locations are worse than others. For instance, at Arnewood Bridge overall we have seen 60% of motorists speeding with 49% of those at over the police enforcement threshold. That's 56 vehicles per hour that could be reported to the police.

Sway CSW is very effective at educating drivers to reduce their speeds; we regularly note drivers slowing down as soon as they observe us and the numbers we see speeding now are lower than when we began in 2014. The problem is that we are only able to be out there for a few hours each month - equivalent over the year to about 1.5% of the time. When CSW are not active, too many inattentive drivers are not being actively reminded of the speed limit.  

 A flashing SLR can be out there 24 hours a day, 7 days a week.

How effective is an SLR?

Anecdotally, most people double check their speed when they see one of these, and most try and slow down before the sign is activated. The reasons why are probably varied and complex, but often it will break down to the simple fact that most people do not want to be seen to be breaking the law. The sign only activates when someone is exceeding the speed limit so it's fairly obvious who triggered it.

Hampshire County Council have stated that on average, vehicle-activated signs have proven to have a beneficial effect on traffic speeds and can reduce traffic speeds on 30 mph roads by around 4% to 7%.

Analysis of the effect that this reduction in the speed of traffic through Sway suggests that this could reduce the numbers of vehicles speeding by anything from 24% to 44%. So for example, if the device was mounted at Arnewood Bridge, the numbers speeding could reduce from 56 per hour down to 42 per hour, and maybe even as low as 31 per hour.

Who will pay for the SLR?

In September 2017, Sway Parish Council approved the earmarking of £5,000 from reserves for the purchase of a Vehicle Activated flashing Speed Limit Reminder along with the infrastructure required to position it at three locations around the Parish.

Where will the SLR be put?

There are strict rules on the siting of such an SLR. It must be somewhere safe and easily visible. Advice from Hampshire County Council is that such a device should be moved regularly, typically every 2 weeks or so. They say that leaving it too long in any one place results in motorists eventually disregarding it.

The chosen locations will necessarily require the full support of Hampshire County Council, New Forest District Council and Hampshire Constabulary.  Hampshire County Council have policies relating to the purchase and deployment of such equipment by the parishes. Guidance from 2010 can be downloaded here.

In October 2017, Sway's Planning and Transport Committee agreed that recommendations on where to locate this SLR should be delegated to the Sway Community SpeedWatch team. Subsequently in November 2017 it was agreed that this process should also involve the residents of Sway through various media including this Parish Council website.

Our purpose here is to explain the project and ask for suggestions from Sway residents on where they think the equipment should be sited.


If you would like to nominate a location where you believe the SLR should be placed, please send your ideas to