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[6][Highways England request email]

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6. mailto:[Highways England request email]

Dear Mr Wood,

I have been passed your enquiry to our Customer Contact Centre (reference
18615094) relating to the M6 on the 28^th of November 2017.

Firstly thank you for contacting Highways England, and reading through
your enquiry I can see that you are requesting a list of “status and
changes to the variable speed limit imposed on the M6 between junctions
10a and 13 on the 28^th of November between 22.00 and 22.45” , alongside
“the reason variable speed limit was operating”.

I have requested and I shall attach a “Halogen report” that shows all
signals set within the area requested, and I have taken the liberty of
widening the time line (I shall explain why I little later in this email)
and I shall also explain what the report is showing.

Prior to that I would just like to share a couple of points with you, the
first being that the vast majority of signals set on the motorway network
are not set by operators within our control room , but are set
automatically by a system known as MIDAS, I shall include within this
email the generic explanation of MIDAS for your information. The second
point that I would like to raise is that Highways England are not a law
enforcing team, we have no police powers and as such we have no speed
cameras, we do not generate an income and do not set speeds on behalf of
the police.

As promised I shall paste the generic MIDAS explanation below, but just to
answer the question “the reason variable speed limit was operating” first,
the reason variable speed limits are in place is purely down to safety and
traffic flow, to simplify the system, the motorway is fitted with sensors
that are built into the carriageway “MIDAS”, these sensors detect traffic
flow and whenever traffic starts to slow or congest it will automatically
reduce the speed on the closest gantry, in the simplest terms this
prevents traffic travelling at motorway speeds encountering congestion or
indeed stationary traffic. The MIDAS system will again automatically set a
secondary speed, prior to the “MIDAS trigger” to gradually slow traffic
down. Once MIDAS has been triggered the relevant speed will remain active
for 2 minutes and if it does not trigger again the speed will be cleared.
As mentioned earlier I have taken the liberty of widening the time line as
it will show where a MIDAS trigger has set a speed, and if traffic
continues to be congested or slow moving, the speed will remain active.

Variable speed limits are an important element of motorways, which have
been in operation since 2006; they have been shown to reduce congestion
and benefit motorists.

At a slightly lower speed, the traffic flows more smoothly, giving minor
congestion a chance to clear before a traffic jam can form, and helping to
prevent the ‘stop-start’ conditions which can occur at busy times. Reduced
speed limits are also used to protect slow-moving or stationary vehicles
by slowing down the traffic which is approaching them.

Variable speed limits are set automatically in response to conditions on
the road, and are only used when necessary. This means that they will only
be seen when congestion is present or when there is a hazard ahead, since
the restriction is lifted as soon as it is no longer needed.

In the context of increasing levels of traffic, smart motorways are a
proven solution which allows us to make the best use of the existing road
space by actively managing the flow of traffic. They are being targeted at
the most congested parts of the motorway network, and are being used to
reduce the congestion which already exists in those areas.

Variable speed enforcement cameras are installed as part of every smart
motorway scheme, and are operated by the Police. Enforcement is one of a
number of measures which are used to encourage compliance with variable
speed limits and ensure the scheme is working as intended. Smart motorways
have brought significant benefits to motorists at a reduced cost, and the
cameras are an essential part of this. Camera warning signs are widely
used to ensure drivers are fully aware that enforcement takes place on
these sections.

Our arrangements with the Police only cover use of the cameras to enforce
variable speed limits displayed on the overhead signals. When the signals
are blank, the cameras are capable of enforcing the national speed limit,
but whether or not this is done is a matter for each of the individual
Police Forces, and Highways England would not be involved in the decision.

The variable speed limits used on smart motorways are usually set
automatically in response to conditions on the road; this allows us to
adapt to traffic conditions ahead which may not be visible to motorists.
If the problem is successfully cleared, drivers may not see what the cause
of the restriction was, although where possible we use the electronic
signing to explain this. The system is designed to ensure that any
restrictions are lifted as soon as they are no longer needed.

Since the speed limits are set in real time, they will sometimes vary
between signals; a difference of 10 – 20 mph will usually have been caused
by a temporary build-up of traffic. The maximum difference in speed limit
between two consecutive signals is 20 mph, and this is used when it is
necessary to slow the traffic down within a certain distance.

Smart motorway schemes are designed with sufficient visibility between
signals to allow drivers time to adjust their speed safely; when the speed
limit changes, drivers who are close to the signal are not expected to
brake suddenly, but rather to reduce their speed so that they are within
the limit as soon as it is safe to do so.

Motorway Incident Detection and Automatic Signalling System (MIDAS).

MIDAS measures the intensity of the traffic using inductive loops
buried in the road. When the number of vehicles rise above certain
predefined thresholds MIDAS sets progressively slower speeds on the
motorway signs and also warns of queues ahead on the Variable Message
Signs (VMS).

This safety measure is intended to gradually reduce the speed of traffic
to avoid sudden braking and bunching, which is a notable cause of
accidents. It also helps to protect the back of any queue that may have
formed. 

These signs are then removed by the MIDAS detector algorithm when it
determines that the queue is easing at the site of the detectors.

Returning to the first part of your enquiry, as promised I have attached
the Halogen report highlighting all of the signals set in the area as
requested. If I could draw your attention to Column D first of all, this
shows speeds or legends showing on road, Column A shows the time, Column C
shows the location, importantly Column E shows who set the signals, and
what you will see is that the vast majority or signals were set “AUTO”
these are MIDAS settings.

I genuinely hope that this email answers your questions, and thank you
once again for contacting Highways England.

Kind regards

A Wood  National Consistency Manager, (Operations Directorate)
Web: [1]http://www.highways.gov.uk

Highways England | West Midlands RCC | c/o The Cube | 199 Wharfside Street
| Birmingham | B1 1RN

Please see a link to the Highways England complaint process:

[2]https://www.gov.uk/government/organisati...

This email may contain information which is confidential and is intended
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recipient, you are hereby notified that any copying, distribution,
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strictly prohibited. If you have received this email in error, please
notify the sender and destroy it.

Highways England Company Limited | General enquiries: 0300 123 5000
|National Traffic Operations Centre, 3 Ridgeway, Quinton Business Park,
Birmingham B32 1AF |
[3]https://www.gov.uk/government/organisati... |
[4][Highways England request email]

Registered in England and Wales no 9346363 | Registered Office: Bridge
House, 1 Walnut Tree Close, Guildford, Surrey GU1 4LZ 

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References

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4. mailto:[Highways England request email]

I am out of office now and will be back in the WMRCC on Monday 22nd of
January.

If you would like to make a request under the freedom of Information Act,
please contact [Highways England request email]

Kind regards

Andy

This email may contain information which is confidential and is intended
only for use of the recipient/s named above. If you are not an intended
recipient, you are hereby notified that any copying, distribution,
disclosure, reliance upon or other use of the contents of this email is
strictly prohibited. If you have received this email in error, please
notify the sender and destroy it.

Highways England Company Limited | General enquiries: 0300 123 5000
|National Traffic Operations Centre, 3 Ridgeway, Quinton Business Park,
Birmingham B32 1AF |
[1]https://www.gov.uk/government/organisati... |
[2][Highways England request email]

Registered in England and Wales no 9346363 | Registered Office: Bridge
House, 1 Walnut Tree Close, Guildford, Surrey GU1 4LZ 

Consider the environment. Please don't print this e-mail unless you really
need to.

References

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2. mailto:[Highways England request email]

Hi Andrew,

Unfortunately we do not have a document that outlines the location of each gantry on the motorway, but I have added a couple of additional columns to the original "Halogen report", column D shows the unique marker post where the gantries are located and column E shows the junctions that the gantries are located between. Sadly I cannot be any more specific than this.

I must emphasise the fact that Highways England are not a law enforcing team and have no police powers, as such we do not have any speed enforcing jurisdiction and have absolutely no knowledge of where police speed cameras are located.

If your enquiry is specifically about speed enforcement, it may be more appropriate to contact the relevant police force for additional details.

I do hope this additional information helps.

Kind regards

A Wood

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