By using computers to aid in the design and
detailing of temporary traffic management control plans,
Andrew Sturrock I.ENG. AMICE, FIHIE argues that there
now is a case for bespoke site-specific design in EVERY
There may be a few readers of this article who will
not understand the significance of what I am saying
in the above headline, indeed there will be some readers
who do not even relate to the words “temporary
traffic management control plans” which put simply
means the signing and guarding of Contra-flows, Work
zones, Road Works, Traffic Accommodation, Diversions
Detours, Lane Closures, Mobile Works, Emergencies, Planned
Works or whatever you call them in your part of the
The basic objective of a temporary traffic management
control plan is to permit the contractor to work within
the public right of way safely, efficiently and effectively
while maintaining a safe, uniform flow of traffic; however
a control plan has many other uses as we shall see later
The collective term “temporary traffic management”
is something of a Cinderella subject for traffic engineers.
Yes, there are a whole host of national standards available
that offer guidance along with legal, contractual and
safety obligations, but it can be left to the people
on site to decide what is needed, can’t it? Well
yes, in certain cases it can - but how does the scheme
originator ensure that the people on site know what
is needed for a particular work site?
Many national highway authorities produce typical signing/delineation
drawings that illustrate various types of roadwork sites;
these drawings are invariably in a schematic format.
Some examples of countries that adopt this practice
USA - MUTCD Part 6H,
New Zealand- Code of Practice for Temporary Traffic
UK - Traffic Signs Manual Chapter 8
Eire -Traffic Signs Manual Chapter 8 (NOT the same document
as the UK version)
These typical layouts usually range from signing for
works on or adjacent to the shoulder, through differing
types of lane closures and mobile works up to complicated
contra-flow arrangements on multi-lane highways.
Given the infinite variety of situations that can be
encountered at any specific work site it would be impossible
for the national standards to even attempt to cover
all scenarios, the best they can do is to show the required/desirable
minimum standards leaving whoever is responsible to
apply the standards indicated on the typical layouts
to the prevailing conditions found on a particular site,
making adjustments and amendments where necessary. But
this then begs the question as to whether a secondary
bespoke drawing (temporary traffic management control
plan) is created using the national standard as a guide
(a mandatory requirement in some countries) or the national
standard is implemented directly on site.
Anyone with experience of the latter task will know
that it is not as straightforward as it may first seem
and it is one of the reasons I am making the case for
bespoke site specific design in EVERY situation.
I concede that in some instances it may be appropriate
just simply to specify the relevant national standard
layout or occasionally it may be sufficient to require
that the principles of a standard layout be applied
to a particular site, for example at a junction, but
then how do you know that the end-user has a up-to-date
copy of the relevant standard or access to the national
specification for temporary traffic management? Answer
is you don’t, and of course in most other circumstances
it is always desirable to produce a bespoke detailed
Consider this: Many types of civil engineering projects
carried out on public highways (from simple maintenance
tasks to large scale improvement schemes) will require
the inclusion of engineering drawings in the overall
scheme documentation. It is all very fundamental really,
the engineering drawings are required for estimating,
planning and construction purposes and without them
it would be very difficult to cost, procure and implement
the project and of course impossible to check the finished
results, never mind ensure that ongoing quality and
standards are being maintained. I would argue that in
addition to engineering drawings the overall scheme
documentation should include detailed bespoke temporary
traffic management designs or at the very least specify
the temporary traffic management to be utilised at a
particular work site. Here are some of the reasons why:
It’s a rare work site that has a full copy of
the national specification for temporary traffic management
available for the workforce to study as an alternative.
If the works are to be tendered, it shows prospective
contractors what has been agreed at the design/planning
stage with third parties (Police, local highway authority,
client, frontage owners, public transport operators,
Reduces liability by showing that the scheme designer
has considered traffic management and not simply left
it to the contractor to prove that the proposed works
are practicable and may be carried out safely. In many
countries it is a mandatory requirement to produce this
level of detail, typically as part of a traffic control
Creating the design well in advance of the start of
works on site allows considered decisions to be made
rather than rushed or perhaps commercially influenced
Gives work site staff access to detailed drawings that
can be worked to/checked against on site.
There are a number of easy to use and affordable software
programs available that have been specifically developed
to aid in the design and detailing of temporary traffic
management control plans.
If the above reasons are not sufficiently compelling,
consider the fact that in the USA alone, over 1000 people
are killed every year at roadwork zones. The safety
of the public and the workforce is not a matter to be
dealt with lightly; it should never be thought of as
“just a few signs and cones”.
So how can we be certain that both the public and the
workforce are adequately separated from each other?
Is it reasonable (or in some countries legal) to leave
the vital safety work of signing and delineating a work
site to the knowledge of site personnel with, as far
as the scheme originator may know, unknown abilities?
I would argue not.
One of the main requirements of temporary traffic management
drawings is clarity. In this respect, schematic drawings
are ideal. The drawings need to clearly show the equipment
(signs, cones, etc.), required in each of the various
sections of a work site. These are usually taken as
— The advance warning area – the approach
to the site where appropriate traffic signs are installed,
advising motorists of the type of traffic management
on the road ahead and what actions they should take
to safely negotiate the site, for example, "left
lane closed” and "reduced speed limit".
— The transition area – the location at
which traffic is diverted from its normal path, typically
a taper where one or more lanes are closed to traffic
by means of cones, drums, barricades or other meansof
— The buffer area – often optional but highly
recommended nonetheless, an area for inattentive motorists
who ignore all the advance signing and the transition
to safely come to a stop in before they crash into...
— The work area, self explanatory, followed by...
— The end of works area – typically ‘road
works end’ signing and perhaps some type of regulatory
signing to indicate to motorists that they have passed
the site and may resume normal driving.
Wherever you find yourself in the world, there are a
limited number of permissible types of signing arrays
that may be erected in the advance warning area. Either
the left or right lanes will be closed or narrowed and
there may be some form of positive traffic control,
whether by means of site personnel with STOP/GO (or
STOP/SLOW) signs or traffic signals. There could be
some type of restriction placed on traffic as it passes
through the site, typically a reduced speed limit but
overtaking, weight, width or height restrictions may
also be encountered. Equally, there are a limited number
of options as to how the other parts of a worksite can
be delineated, with traffic passing through the site
in varying numbers of lanes, perhaps using a paved shoulder
if one is available.
To a motorist approaching or passing through, a work
site can often look very complicated, but the basic
principles are very simple, especially if you consider
each part of the diagram as a single building block,
and that each of these "building blocks" can
be placed together to form the basis of a site specific
layout. Given access to a photo copier and a pair of
scissors then fairly detailed layouts can be achieved
quite quickly using the old “cut and paste”
However, what can be achieved by hand in most cases
can be achieved many times faster using a computer and
will include extra benefits. Modern computer aided design
(CAD) software lends itself to producing the various
combinations required to create site specific layout
drawings and includes a whole host of added benefits.
The reasons for using CAD are the same as using word
processing: It saves time and money by taking care of
the mundane tasks so your creativity can be used elsewhere.
Diagrams created using a CAD systems are of better quality,
are more accurate, and consistent. Rapid changes can
be made to existing layouts, its easy to mirror and
copy, great for “handing” the layout, modifications
such as changing variable text are easy tasks to perform,
I could go on and on listing the benefits of CAD but
I am also making the case for bespoke site specific
temporary traffic design in EVERY situation and simply
going out and buying a CAD system and obtaining or downloading
a bucket load of typical drawings from the internet
will not in itself help.
A key advantage of CAD as opposed to manual methods
is the ease of creating multiple copies of entire drawings.
Imagine a mile long urban road with number of tee and
cross junctions, you can create an initial temporary
traffic plan at the start, add in details for the first
set of junctions, now copy and move the whole lot along
the road, make minor adjustment as necessary and repeat
over and over again and before you know it you have
just created a whole set of plans for the entire road
in a fraction of the time it would have taken you to
create one by manual methods.
As I previously mentioned, typical drawings available
from the Internet or other sources will not necessarily
help you; these “drawings” could be in incompatible
file formats (PDF, DDW, CD, DGN and TIF typically for
use with Adobe, AutoCAD, COREDRAW or MICROSTATION).
Now the worlds most popular CAD system is AutoCAD and
maybe you or your employer have made wise decisions
and you have access to a full or LT based AutoCAD system,
you are still not home and dry. A key aspect to the
rapid creation of similar traffic control plans is the
“building block” with “minor adjustment”
approach, so the individual parts (the building blocks)
must be compatible with each other, have correct scale
and have common reference points in order that they
can be joined together and they must be able to be easily
modified. Simply having access to these “intelligent
blocks” is also not enough you will also need
an easy to use interface, a good management system and
a set of “special” tools help you along.
Of course the ideal software tool that helps you achieve
this id CONE.
In summary, the implementation of protection measures
for both the public and the workforce on public highways
are not matters to be considered lightly.
Well thought out and sufficiently detailed drawings,
showing where and how signing and delineation measures
are to be installed are a vital part of this protection.
Modern CAD methods offer a cost effective, high standard
method of achieving this requirement.
There is no need or excuse for poorly planned and executed
Andrew Sturrock is a highly regarded, nationally
recognised exponent and authority in the design of traffic
control plans and he helped over a period of years to
improve the standards of temporary traffic management.
He is employed by WSP, an international engineering
consultant, and currently seconded to CarillionWSP in
the Yorkshire area. Both companies are leading exponents
in the field of highway and motorway maintenance, holding
several such commissions both in the UK and abroad.