Written evidence from Vysionics ITS Ltd. (RTL0010)

Briefing Paper – Average Speed Cameras

8th October

Geoff Collins, Director, Vysionics ITS Ltd.  A developer/supplier of Home Office Type Approved digital enforcement solutions.

1.    Overview

The UK’s first average speed camera received Home Office Type Approval for unattended enforcement in 1999, when it was installed along an urban route in Nottingham.  Since then, the technology has been used in 350+ temporary road works schemes and 70+ permanent route management projects.  Overall, the casualty reduction effect of this technology has been significant; at sites where it is used as part of a casualty reduction measure, Killed or Seriously Injured (KSI) rates have dropped on average by more than 70%.  In addition to this, wider societal benefits are seen through improved traffic flows, reduced emissions and a greater level of public acceptance.

2.    Locations

To date, over 400km of trunk roads and 200km of Local Authority roads are monitored by SPECS cameras, covering speed limits of 20, 30, 40, 50, 60 and 70mph.  A typical scheme will be around 10km in length, but the longest operational to date is the A9 in Scotland, covering 220km of road.  ASC are used on single carriageway, dual carriageway and motorways, usually at sites where there has historically been a high casualty history.  A small number of sites have been installed as part of a Traffic Management solution, due to the improved flows that are delivered by ASC, or as a risk mitigation measure due to a change in road configuration.  The A9 will be used to illustrate a number of the points raised below, as it is recent and Europe’s most significant enforcement installation.

3.    Benefits of Average Speed Camera Enforcement

The uptake of Average Speed Cameras (ASC) has been rapid, largely due to the apparent benefits that highways and road safety professional have seen through practical experience of their use.  There has been little independent review of their effectiveness, but this is being addressed by the RAC Foundation, who have recently commissioned a research project to evaluate the effectiveness of ASC across the UK. 

Unlike some localised safety or Traffic Management interventions, ASC is seen to deliver a number of mutually advantageous benefits which have a large zone of influence, covering long sections of road or regional corridors.  These benefits are improved safety, traffic flows and environmental considerations as well as a greater level of public acceptability:

a.     Safety

Most ASC sites are installed to address a significant casualty history, of a kind that could not be easily solved with alternative interventions.  Example schemes will usually see high casualty levels along an entire route, rather than at a specific ‘accident blackspot’.  To carry out a meaningful review of casualty reduction, it is usual to compare three year baselines with three years of post installation data.  Looking at SPECS installations that were installed as a casualty reduction measure, the Killed or Seriously Injured casualty (KSI) figure on average drops by >70%, which has a theoretical saving to UK plc of > £1m per year, per site.  Individual sites do see different levels of KSI reduction, but no permanent SPECS site has ever seen an increase to the KSI figure, with reductions of between 100% in the best case and 25% as a ‘worst case’ scenario.

b.    Traffic Flows

In addition to the casualty improvements, ASC control results in a steadier, smoother flow of traffic, comparable to the flows seen within Managed Motorways.  By harmonising traffic speeds journey times become more uniform, resulting in improved journey time reliability.

c.      Environmental

When traffic is flowing steadily and near to the posted speed limit, the vehicles’ engines burn less fuel and produce fewer emissions.  In addition, the engine noise, vibration and wear and tear to the highway infrastructure will be eased, meaning that the local environment will be improved for both road users and residents.

d.    Public Acceptability

ASC schemes work best when they are introduced with other route improvements such as renewed signing and lining and other low cost improvements.  There is now a significantly higher level of acceptance from the road using public, and for a number of reasons.  ASC cameras do not ‘catch’ drivers unawares, as they have to maintain a speed in excess of the limit over a large distance compared to spot speed cameras. Compliance with ASC tends to be much better than spot speed systems and only around 1 in 10,000 drivers passing through an ASC controlled zone will typically receive a speeding ticket as not all zones will be live at the same time, which helps to reduce the accusation of unfairly targeting sensible drivers.

4.    Driver Behaviour within Average Speed Camera Controlled Zones

The benefits of ASC outlined above are routinely seen through real world examples, but it is important to understand why such an approach actually delivers these results.  The key factor to consider is speed harmonisation:

a.     Speed harmonisation

Variability in vehicle speeds is the enemy of safety, journey reliability and the environment.  Where there is a high standard deviation of vehicle speeds, road users come into conflict – either with fast vehicles trying to overtake slow ones, or through the ‘shock wave’ effect of sudden braking.  The chart above shows a typical speed profile, taken from a SPECS monitored zone on the M4.  It can be seen that there is very little variability in vehicle speeds, from the fastest to slowest vehicles.  This is because virtually all drivers are deliberately complying with the posted speed limit, because they are aware that their speed is being actively monitored, and over a significant length of road.  Not only does this mean that speeds are uniform, or harmonised, but it also means that vehicles are far less likely to collide with each other, due to the small speed differentials on the road at any one time.  Above all other factors, this results in the better flows and reduced casualties.

5.    Design & Operational Considerations

Simply installing technology at the side of the road will not automatically deliver the benefits discussed above – the design of a site is key to making it functional and effective.  All UK SPECS sites are first and foremost designed to be extremely conspicuous, with the primary intention being to deter, rather than detect offenders.  This is achieved through the use of 878.1 ‘Average speed check’ signage, along with cameras painted yellow, usually mounted on dedicated columns which are also yellow.  This not only reduces the ‘out to catch law abiding drivers’ argument, but also helps to manage driver behaviour throughout the monitored zone.  It is deliberately not clear where the enforcement links are located, so drivers treat the entire monitored zone with care, rather than reacting suddenly (hard braking) to a specific camera location.

A further key consideration is the enforcement regime to be followed within an ASC controlled zone.  Whilst it is possible to make all cameras at all locations live simultaneously, it may not be a good idea. Even with the excellent compliance seen through ASC, a fraction of a percentage of offending drivers on a high volume strategic road will quickly mount up, if it is continually monitoring every journey.  The A9 example results in around 15 journeys per day that will result in further action – this is achieved through very high compliance, but also because the live links and sections are dynamically managed, allowing for a flexible enforcement strategy.

6.    Future Considerations

Currently, the Home Office Type Approval (HOTA) that regulates the use of automated enforcement systems limits a device to only being able to carry out one task – i.e. if camera is carrying out speed enforcement, it cannot simultaneously carry out Police ANPR or journey time measurements. If this requirement was relaxed, with appropriate safeguards, much better use could be made of the data to the benefit of all road users and operators.

Clarity of purpose/message is also key if using technology to support safety and congestion projects on the highway.  The travelling public are much more accepting of control and enforcement measures if they are understood and perceived to be meaningful/fair.  This is delivered through good design, collaboration, consultation and unified, clear message through the media.

October 2015