Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Innovative and Collaborative Construction Engineering


Paraskevi Michalaki

Project Title

Estimation of a risk profile to operatives and the public from motorway hardshoulder incursions


Balfour Beatty Capital


Dr Mohammed Quddus
Dr David Pitfield

Mr Andrew Huetson
Mr Andrew Dean

Director of Research:
Professor Stephen Ison

Research Period

2012 - 2016

Estimation of a risk profile to operatives and the public from motorway hardshoulder incursions

Company Background

Connect Roads is a subsidiary of Balfour Beatty, the world-class infrastructure services business. Balfour Beatty operates across the infrastructure lifecycle and is the largest company working within the UK highways sector, which includes the PFI market.

Balfour Beatty has four market-leading businesses in professional services, construction services, support services and infrastructure investments. Balfour Beatty Capital is the infrastructure investment business and has committed equity investments of £415 million in 41 projects. It is an equity investor in highways and street lighting facilities under the UK Private Finance Initiative (PFI) through its Connect Roads business. Connect Roads is one of the UK’s largest private sector road operators which includes five concessions and the M25 London Orbital, via its sister brand Connect Plus.

Connect Roads operates and maintains 360km of trunk road network servicing 2.8bn vehicle-km. In partnership with its Term Maintenance subcontractors, Connect Roads undertakes all the operations and maintenance requirements for those routes, and working with its clients, the Highways Agency and Transport Scotland, identifies and delivers improvements focusing on Journey Time reliability and Road Worker/Road User Safety.

Current State-of-the-art

The Zero Harm (ZH) Safety Initiative introduced throughout the Balfour Beatty (BB) Group of Companies in 2009 established forums at all levels for staff and employees to identify, examine and where possible eradicate H&S issues in the workplace. These forums are platforms for the direct workforce to raise concerns both within their direct working environment and of construction practises in general. Directors also undertake Safety Deep Dives and talk openly with the site teams about their personal concerns for safety and ask them to identify and recognise their own biggest risks out ‘on the job’.

Via Connect Roads, Balfour Beatty Capital (BBCap) holds a dual role as Agent to the Highways Authorities (Highways Agency (HA), Transport Scotland (TS) and Cumbria County Council (CCC)) and as Client to subcontracting in-house BB Group companies (BBMCE, BBRCE and BBW) who undertake its routine term maintenance and life-cycle renewals. Across several of its ZH workshops a common thread, perhaps not apparent to the individual companies’ ZH sessions, began to develop of near misses with 3rd party vehicles straying onto the hardshoulder where they were working or were parked. Operatives of the individual companies have to work from the hardshoulder and recognised slightly different hazards, which as separate clusters may not have been picked up to have the same causation- the behaviour of the adjacent traffic. (Their hazards were working directly on the hardshoulder, access to a work site on the verge, parking vehicles when maintaining roadside equipment, attending road user breakdowns and accident incidents.) Each group reported several near misses from vehicles veering from the Driving Lane (Lane 1) across the ribbed line into the hardshoulder near to where they were situated, and there was absolutely nothing they could do about it.

As stated, BBCap is a central player in the Highways Maintenance Community and once it captured this common theme with its in-house subcontractor groups –indeed hardshoulder incursions is one of its five major actions within its ZH Journey Plan- took the issue to the general highway stakeholder community outside BB to look at their experiences and research. These groups included the HA’s Traffic Safety officers, a service that patrols the motorways and responds to traffic issues including attending stopped vehicles, the police and NRTS, who look after the communication systems, cameras and signals. They could provide no answers but added their own concerns, with the police adding their concern for members of the public stopped out on the hardshoulder. Advice to them is well known – get out to a position of safety- directly because of this incursion issue. However, no precise figure or reason, risk level or factor could be put to the problem.

Concerns were also raised about the increasing squeezing of current network assets with managed motorways and hard shoulder running, the fact traffic volumes continue to grow, possible reductions in service levels of direct attendance and camera monitoring and associated response times and the possible adoption of risk base approach to such services.

The evidence was still anecdotal, but during a semi-annual ZH session with subcontractors and partners our traffic counting subcontractor suggested they might be able to count the incursions during the video verifications. (BBCap are paid on shadow tolls and need to physically count the traffic for a two hour period each month at the counter sites to check they are accurate.) The results were startling. Every 15 minutes, at that one point, a vehicle strayed across the white line into the hardshoulder and 98% of those are HGVs.

BBCap’s initial review on Hardshoulder Incursions (HI) concluded that the risk was significant, but measurable, and needed much further investigation as nobody else in the community had any data on the subject. In order for BB to close out its ZH action to be able to effectively control and manage HI risk then it would have to undertake its own work. This would be of direct benefit to the whole Motorway Community and the Highways Agency, so that all members could work with more confidence from knowing the levels of risk, the quantum and scale of effects of any mitigation measures.

There are perhaps two important factors to tackle: when and why. By analysing the Whys we should be able to predict the probability of the When.

Aim and Objectives

In light of the research problems described above, the aim of the proposed project is to explore and quantify the risks of Hardshoulder Incursion (HI). This is formulated in the following


  • To investigate the various factors affecting the occurrence of hardshoulder incursion
  • To develop a ‘black box’ counting tool that can be used anywhere on a motorway network to collect the required data related to incursions 24/7/52
  • To identify appropriate statistical models so as to develop a Hardshoulder Risk Matrix that network managers can use to model their routes, design safe zones for high risk sites
  • To produce a 3rd Party Risk Matrix for risk based approaches to emergency responses on the Hardshoulder
  • To develop models for estimating the magnitude of overrun given a hardshoulder occurrence
  • To formulate a range of risk mitigation measures related to HI

BBCap want all the Motorway Community Shareholders to be able to show its workforce it is not putting them at undue risk by using this model to assess the likelihood of probable collision events to a stationary vehicle on the hardshoulder. These levels can be agreed with the operatives and road authority and where they are exceeded, works could be delayed or other safety measures used to manage that risk.

The project would look into the multiplicity of variables on the motorway network from its own physical characteristics, traffic flow, times of day, weather.

The project also needs to determine the magnitude of the overrun. Hardshoulders vary significantly in width. The magnitude of overruns may be greater in certain circumstances making collisions more likely.

By examining all these variables a mathematical model can be developed to accommodate all situations that may happen on a motorway. We envisage a Risk Matrix being determined which can be used on all motorways, so that a manager can create a traffic light type map of his network to guide his operations. This may require various layers for changing external factors but essentially the manager should be able to know and understand the potential risk at any time and make a judgement on deployment.

Incursions inside traffic management are also a hazard noted by roadworkers. The techniques developed by the hardshoulder incursion study should be transferable to the Traffic Management situation. Again, journey times and disruption are pushing Traffic Management layouts to narrow lanes and longer lengths, which are being reported via Near Miss reports to have higher strike rates. A study for TM could be a useful off shoot of this work.


In order to achieve the above objectives, a range of research methods need to be employed. First of all, an in-depth literature review on hardshoulder incursions will be conducted so that factors affecting such occurrences can be identified. A state-of-art review of current industry practices will also be needed to identify devices that can be put together for collecting the necessary data. A range of statistical models (e.g. random-effect or fixed-effect Poisson or Negative Binomial models) suitable for count data (i.e. hardshoulder incursions) will be explored to identify the best statistical model for estimating the number of incursion occurrences per unit time for a given scenario (i.e. specific traffic conditions, road geometry and weather). To estimate the probability of an incursion (or incursions) per unit time (e.g. 15 minutes), other statistical models such as binary or multinomial logit/probit models will also be explored. Such statistical models will also be employed to estimate the magnitude of overrun given that an incursion has occurred. Data need to be collected from a range of sites (varying with traffic characteristics, road geometry and weather conditions) so that a robust model can be developed.

Benefits/Expected Outcomes

With a Hardshoulder Incursion Risk Matrix (HSIRM) highway maintenance service providers and stakeholders will be able to address their duty of care to provide as safe as possible working place for its operatives. That is, both from a day by day perspective and helping towards designing solutions for difficult situations where a roadside presence cannot be avoided. Further, it will allow external factors to be monitored which may change the risk profile and allow the on-ground operations to react to this.

It may allow a cost saving, targeted response to “public vehicular breakdowns” to be developed, as it will allow resources for recovery to be risk orientated. It will also give a prescriptive measure for the necessary deployment of disruptive TM installations in such circumstances, especially during busier periods when there is central pressure to maintain journey times.

Traffic has long been the number one personal safety concern of the BB roadworker. The HIS Risk Matrix will give him confidence that the risk to his well being is minimised at all times and locations. And it will give management a barometer to a safe presence on the network at any given time and set of circumstances.

However much as the HSIRM can be used to avert or alert the HSI risk we must recognise incursions are mostly due to driver behaviour and not the result of 2nd or 3rd party behaviour. The fact that road conditions (2nd party) can exacerbate the HSI likelihood or severity (the whole reason for the HSIRM) does not mean the initial cause, driver behaviour, should be overlooked in the study –even if the outcome of the study cannot affect this. The study ought to address driver behaviour reasons directly and aim to use itself as base evidence to engage road user groups to improve their performance.

That said the study should also look at possible methods of engaging road users attention i.e. highlighting the immediate presence to approaching traffic. This is complicated by general road user distraction and issues pertaining to visibility (dark/dusk, rain/spray) and practical deployment (duration, portability, ability to deploy without risk).

The project would be a starting point, which can be both monitored by use of a series of recorders across the UK and developed and refined. The purpose of this would be part of the engagement with road user groups to determine the effectiveness of driver behaviour initiatives and on-going improvements.

Ultimately, we are expecting this to be rolled out nationwide for use and adoption by the maintenance community and for road safety advise to the travelling public.



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The Centre Administrator
Loughborough University
LE11 3TU

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