Analysis: Of speed and its limits

02/05/2018
Dom Browne

One of the key aspects of innovation is that you can't be afraid of (safety monitored) trial and error. Every bold step forward requires a background of missteps and not-quite-perfect attempts.

In the era of big data and computer learning, this process is happening all around us all the time with many systems evolving and adapting with use in real-time.

It is within this context that the news that Highways England will be carrying out a 'comprehensive review' of variable speed limits on motorways, after admitting that lower limits were not always correctly set, is to be welcomed.

”Local
 

Highways England chief executive Jim O’Sullivan explained that 40, 50 or 60mph limits were being set as a preemptive measures when congestion was expected to mount on ‘smart motorways’ in England, using predictions about traffic levels.

He also admitted that there was ‘dissatisfaction’ among some motorists when the expected build-up failed to materialise, forcing them to drive slowly along free-flowing roads

As Highways understands it, part of this issue is likely to be because the system is working well to prevent the predicted congestion and part of it is because the system is, understandably, not quite perfect yet and speed restrictions are being triggered for the wrong reasons or maintained for too long.

Highways England has done the right thing in being open about this and the review is not just as good news for drivers, but good news for professionals and the systems they seek to refine.

Highways received a briefing on the background to this, which demonstrates some of the complexity that goes behind this issues.

Highways England traffic officers have control over a manual system on smart motorways, which have variable speed limits and the potential to open the hard shoulder for all lane running. These officers are directly responsible for core tasks like opening up a hard shoulder.

However there are also elements to the variable speed limits system that operate under an automatic algorithm system for regulating speed. Apparently anomalies on the network, such as a particularly slow moving car, can lead to the automatic system being triggered and unnecessary speed restrictions being put in place for unnecessary amounts of time.

Traffic officers are being trained in how to spot and override this, while the review could help evolve the background system and its algorithm.

Highways England did a piece of research and trial analysis looking at traffic flow on the strategic road network in the North East from February to March this year compared with February to March last year.

The research highlighted some of the issues with the algorithm system that need further development, hence the comprehensive review.

The review could take 12 months over this financial year and would take into account next February and March's data and hopefully provide enough information to tweak and finesse the automatic algorithm system for regulating speed.

However Highways England stressed this will be an ongoing process, as the government-owned company seeks to take away driver frustration as and when it arises.

Highways England executive director of operations Nick Harris said: 'Variable speed limits help keep drivers moving by smoothing the flow of traffic and improve safety for all road users. We have trialled an improvement to the signal settings to reduce the length of time these are set to help restore the national speed limit quicker to further improve journeys.'

One issue that needs to be considered alongside this is speed enforcement. 

Data obtained under by the Times under Freedom of Information showed that 72,348 people were fined on motorways with variable speed limits last year. This was almost double the number a year earlier and a tenfold rise in five years. Of those, two thirds of fines were imposed on motorists driving at 69mph or below, even though the national speed limit is 70mph.

This suggests that the majority of people are being fined for speeding when variable speed limits have been put in place. One potential solution to this is the introduction of average speed cameras along certain routes.

Average speed cameras do not currently operate on smart motorway sections, i.e. where the speed varies.

The system has worked well on the A9 in Scotland, and despite the usual initial concerns over over-zealous enforcement, the use of average speed cameras has been celebrated by Scottish ministers as a major step forward in road safety. 

It might make a nice irony if they also saw people fined less on English motorways.

Highways jobs

Technician - Structures

Milton Keynes Council
£24,799 - £28,785
We’re looking for talented individuals to be part of our expanding team working on everything from local schemes to... Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Assistant Director – Planning, Transport & Public Protection

Thurrock Borough Council
Up to £104,000 per annum
Team Thurrock Essex
Recruiter: Thurrock Borough Council

Waste Prevention Manager

Camden London Borough Council
£45,504 - £52,786
We have an exciting opportunity available for a manager with an expert knowledge of waste prevention and a collaborative approach, to... Camden, London (Greater)
Recruiter: Camden London Borough Council

Senior Engineer - Structures

Milton Keynes Council
£44,632 - £49,298
Milton Keynes is a place of opportunity. Milton Keynes
Recruiter: Milton Keynes Council

Head of Infrastructure & Transport

South Tyneside Council
up to £85K
This is a fantastic opportunity for an outstanding leader to join a high performing Council. South Tyneside, Tyne and Wear
Recruiter: South Tyneside Council

Team Leader - Highways

Milton Keynes Council
£50,941 - £54,228
Milton Keynes is a place of opportunity. Milton Keynes
Recruiter: Milton Keynes Council

Highways Traffic Development Engineer

Milton Keynes Council
£34,788 - £38,813
Milton Keynes is a place of opportunity. Milton Keynes
Recruiter: Milton Keynes Council

Assistant Contracts Engineer

Milton Keynes Council
£34,788 - £38,813
We are looking for an Assistants Contracts Engineer to be a key senior member of our Contracts Team managing... Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Team Leader - Streetworks

Milton Keynes Council
£39,782 - £43,662
We are looking for a Team Leader to lead our Streetworks Team. Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Traffic Project Officer

City of York Council
£26,875 to £29,783 per annum
City of York Council have a great opportunity for a Projects Officer to join our busy Traffic Team. York, North Yorkshire
Recruiter: City of York Council

Traffic Management Leader

City of York Council
£35,500 to £40,710 per annum
City of York Council have an exciting opportunity for an experienced transport professional to lead our Traffic Team. York, North Yorkshire
Recruiter: City of York Council

Senior Technician (Structures)

Milton Keynes Council
£29,636 - £33,779
With several future projects coming up this is an exciting time for an experienced Senior Technician to join our team.  Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Senior Engineer - Development Management

Milton Keynes Council
£44,632 - £49,298
We are looking for a Senior Engineer to work within our Development Management Team. Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Principal Transport Officer (Policy)

St. Helens Metropolitan Borough Council
£38,813 To £40,760 per annum
This is an exciting opportunity for an energetic and motivated individual to drive forward transport policy to... St Helens, Merseyside
Recruiter: St. Helens Metropolitan Borough Council

Road Safety Officer (Education and engagement)

Milton Keynes Council
£29,636 - £33,799
We are looking a Road Safety Officer to deliver our education and engagement programme across Milton Keynes. Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Road Safety Engineer

Milton Keynes Council
£34,788 - £38,813
We are looking for an experience Road Safety professional to join our team to process and analyse collision and casualty data and to... Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Development Management Engineer

Warwickshire County Council
£37,849 - £39,782 per annum
The successful applicant for this post will be capable of taking the lead on work within... Warwick, Warwickshire
Recruiter: Warwickshire County Council

Project Officers

Buckinghamshire Council
£29121 - £38881 per annum
OverviewCareer graded posts 5-7£29,121 - £38,881 per annumThis is your chance to make a lasting impact on our county. From developing the connected tr England, Buckinghamshire, Aylesbury
Recruiter: Buckinghamshire Council

Permit Coordinator

Milton Keynes Council
£29,636 - £33,799
We are looking for a Permit Coordinator to work within our Streetworks Team. Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Highways Liaison Officer

Milton Keynes Council
£29,636 - £33,799
We are looking for a Highways Liaison Officer to join our Communications and Liaison Team. Milton Keynes, Buckinghamshire
Recruiter: Milton Keynes Council

Highways on Fridays

Register now!

Latest Issue

latest magazine issue

 

ADEPT: Past and present

Highways England: Present and future

Mott MacDonald: Urban realm of the future

View the latest issue

Latest Video