The sun streamed through the slightly dusty windows of the Alton branch of Costa Coffee, as I sat enjoying my coffee, catching up with the news, both digital and conventional.
An article caught my eye about road safety, so, having had my curiosity piqued, I conducted some research which I found very interesting, and in the spirit of friendship and understanding, I offer my thought to you, gentle reader.
Speed Cameras. Love them or loathe them, they do serve their purpose, which is reducing speed, and increasing safety. However, adherence to the speed limit isn’t the sole factor that a driver is monitoring, particularly when driving in heavy traffic, or demanding road conditions. Distraction management is not a skill that is taught during driving lessons, and maybe it should be.
It would appear that most Police Authorities are aware of this weakness, and allow for a tolerance in speed keeping, to ensure that motorists are not penalised unfairly for a momentary breach of the speed limit.
Most police forces in the UK have confirmed that they allow for a 10% error plus a 2 mph additional tolerance to account for minor lapses in driver speed control. This is an agreed standard set by the National Police Chief’s Council.
As far as I am aware, this margin was originally put in place to account for the inaccuracies of early speedometers, which were cable driven from either a gearbox on a road wheel, or from the vehicle transmission gearbox. I have also heard anecdotally, that the additional 2 mph was to account for what we could call distraction error.
A recent Freedom of Information request made by Auto Express© (www.autoexpress.co.uk) to UK police forces confirmed that 22 constabularies adhere to the guidelines, and cameras are calibrated to trigger at the posted speed limit plus 10% + 2 mph (i.e. in a 30 mph limit, a camera will trigger at 35 mph, in a 40 zone at 46 mph etc)
The remaining eight constabularies declined to offer full details of the trigger tolerances, which is a shame, but understandable.
According to a study conducted by the London School of Economics and Political Science,  speed enforcement cameras reduced accidents by between 17 to 39 per cent, and reduced fatalities by between 58 to 68 per cent, so they are definitely an effective measure in improving safety.
Interestingly, speeding accounted for 60 per cent of all fatal accidents in the UK in 2015.
However, whilst the cameras reduced accidents within 500 metres of the site, accidents outside the camera zone increased, as drivers either braked suddenly to ensure they were in compliance with the limit, or accelerated heavily once outside the camera’s operational range.
As a result of this behaviour, more and more speed limits are now enforced with average speed cameras, which ensure compliance over a greater distance, and without the related dangers of braking and accelerating in the locality of the speed camera site. This works very well, as I can testify to.
One of my regular routes takes me up the A3 towards London. Just south of Guildford, the national 70 mph limit drops to 50 mph, in the area known locally as Wooden Bridge. Up until recently, it was almost impossible to maintain 50 mph in safety due to aggressive tailgaters, dangerous filtering and regular high speed lane changes and sudden lane changes.
A few weeks ago, Average Speed Enforcement was activated, and as a result, most drivers now comply with the 50 mph limit, and aggressive tailgating is negated by the need to maintain 50 mph.
Human behaviour, being what it is, means that wherever it appears safe to breach the rules, then a driver will consciously break the limit. I admit that on an empty motorway, I often take a calculated risk and drive at 80 or 90. I have done so on a number of occasions, when my experience and perception indicates to me that it is safe to do so. I say that with the benefit of 42 years of driving experience, both on motorcycles and in cars.
It often appears that the authorities are willing to reduce speeds when appropriate, but not to increase speeds when the conditions warrant it.
Across the EU, they take a sensible and pragmatic approach. In France for example, I have seen a limit of 130 kph (81mph) with a further sign reducing the limit to 110 kph (68 mph) in rain. Across the Netherlands, the Autoroute limit is 130 kph as well, so 10 mph faster than the maximum speed limit in the UK. So much for EU unity!
As it appears that drivers are incapable or unwilling to abide by speed limits, which to be fair, are generally there for the safety of all road users, the EU is now is now mandating that all vehicles manufactured after 2022 will be fitted with Intelligent Speed Adaption (ISA).
There is currently a lot of mis-information about what is perceived as external speed control. ISA is designed to complement the driver’s speed keeping discipline, and will intervene should the speed limit be exceeded.
ISA is an onboard system that tracks the vehicle’s position by GPS, and compares the co-ordinates with a speed limit database. The system then continuously monitors the vehicles speed.
ISA will be designed to offer three modes of operation.
At the most basic level, should ISA detect a breach of the posted limit, an audio/visual warning will be generated to alert the driver. This is referred to as an “Open” system. This is an advisory system only, and the driver may choose to ignore the system-generated warnings.
Should the authorities decide that the system should be more robust in its levels of intervention, then either a “Half Open” or “Closed” system will be mandated.
The Half Open system will be designed to provide force-feedback through the accelerator pedal should the posted limit be exceeded, thus giving the driver not only an audio/visual warning, but a sensory input that actively resists the foot pressure delivered to the accelerator. The driver would then have to consciously make an effort to overcome the feedback pressure. This enables a driver to breach a posted limit in the event that an emergency condition dictates it.
Lastly, is the “Closed” system, which actively prevents the speed limit being exceeded, and gives the driver no means of intervention
There are obviously drawbacks to the ISA as a system.
Firstly, there is a risk that further automation of the driver’s interactive functions will reduce the level of awareness and involvement, potentially leading to a reduction in attention to road and traffic conditions. Loss of awareness is highly dangerous, and could in itself lead to further accidents.
Secondly, once a driver has accepted the use of such a system, there may be a tendency to become over confident, with a perception of invulnerability as the system effectively manages maximum speed. However, as the system only monitors compliance with the maximum speed, the driver needs to remain involved and “in the loop” as conditions may dictate a much lower speed for safety.
Some drivers may also become frustrated at the system holding them at what they consider to be a speed that is too low for safety, especially where speed limits have been set arbitrarily rather than as a result of evidence based decisions. This may result in risk based behaviour.
So, vehicles are becoming much more automated, and much work needs to be done on developing that man-machine interface.
I am so glad that I enjoyed driving as a young man during the years when there were no speed cameras. As a country teenager, I took my chances with getting caught by the police whilst rocketing around the lanes of Sussex at lunatic speeds. I was lucky that I enjoyed this without sustaining a crash, injuring or killing anyone else, and without receiving any driving bans.
This is a privilege that is denied younger drivers now.
Brave new world?
Mark Charlwood© May 2019
 Figures from 1992 – 2016 Cheng Keat Tang PhD
 Within 500 metres from the camera site