Road Tunnel Safety Research Articles

The Integrated Strategies for Fire Safety of Long Road Tunnels in Taiwan

The Guanyinshan Tunnel opened in 2009 allowed passages of large chemical tankers. To ensure public safety, subsequent researches on fire safety design in a road tunnel in which dangerous goods are allowed to travel through were performed. The research results then led to the debate of effectiveness of the tunnel fire safety and to a consensus on the need for installation of water-based firefighting system (WFS) in the tunnels of Suhua Highway Improvement Project. The evolution of integrated fire safety management and design in long road tunnels has positively impact the fire safety industry, academia and transportation in Taiwan. This study proposes a new integrated fire safety strategy for long road tunnel in Taiwan based on the simulation inference of fire scenarios, design specifications, and project management in Japan and European. In this study, two-bus fire scenario in a road tunnel are analyzed using the fire dynamic simulators (FDS) program and a safety assessment method is developed for human evacuation and rescue operations in a road tunnel fire. A time constraint of 7minutes for firefighters to engage in firefighting activities is determined on full scale experimental results and simulation results. Based on the assessment and field survey results, an appropriate firefighting scheme can consequently be determined. The results of this study serve as a useful information for road tunnel fire safety design and strategy of emergency response management.

Introducing the STAMP method in road tunnel safety assessment

After the tremendous accidents in European road tunnels over the past decade, many risk assessment methods have been proposed worldwide, most of them based on Quantitative Risk Assessment (QRA). Although QRAs are helpful to address physical aspects and facilities of tunnels, current approaches in the road tunnel field have limitations to model organizational aspects, software behavior and the adaptation of the tunnel system over time. This paper reviews the aforementioned limitations and highlights the need to enhance the safety assessment process of these critical infrastructures with a complementary approach that links the organizational factors to the operational and technical issues, analyze software behavior and models the dynamics of the tunnel system. To achieve this objective, this paper examines the scope for introducing a safety assessment method which is based on the systems thinking paradigm and draws upon the STAMP model. The method proposed is demonstrated through a case study of a tunnel ventilation system and the results show that it has the potential to identify scenarios that encompass both the technical system and the organizational structure. However, since the method does not provide quantitative estimations of risk, it is recommended to be used as a complementary approach to the traditional risk assessments rather than as an alternative.

The evaluation of different evacuation models for assessing road tunnel safety analysis

The current state-of-the-art presents a multiplicity of evacuation models for simulating emergency scenarios. Each model involves different methodological solutions to represent the same process and each one has its strengths and limitations. In addition, they have their own specific features and often practitioners do not have a thorough understanding of the variables that could be input into the models and how they will affect the results. Thus, there is a need to analyse the differences between the models, why they occur and how they affect the calculations. This study compares three evacuation models (FDS+Evac, STEPS, Pathfinder) and the analytical calculations provided in the Society of Fire Protection Engineers (SFPE) Handbook, each of them using different simulation methods. The case-study is the Lantueno tunnel in Spain (a two-bore road tunnel with an emergency link tunnel between the two bores). The results initially show that, when considering evacuation scenarios with a single available exit and favourable response times, the obtained evacuation times do not differ significantly between the models. In a second step, the analysis of more complex scenarios has allowed the determination of the main factors of occupant–fire interactions that cause the differences between the models: the use of unfavourable pre-evacuation times and the exit selection process under low visibility conditions. These differences occur in relation to: (1) modelling method, (2) degree of depth of the analysis of the fire conditions during the calibration of the inputs, and (3) user’s experience in applying appropriate safety factors when using only one model.

Road Tunnel Safety: HGV Driver Training in France

From 2004 to 2009, The Tunnel Studies Centre(*) (CETU) led a research program on the role of human and organizational factors in road tunnel safety. This work produced several insights into human behavior. Generally speaking, drivers do not adopt the expected behavior in tunnels, particularly in cases of fire. These insights led to proposals for concrete actions to improve road tunnel design and operational organization, as well as user-targeted education and training initiatives. Several innovative concepts have recently been developed on the basis of this research work. Following a brief summary of previous user education actions, the paper discusses French initiatives to improve initial and further training of HGV drivers with respect to driving in road tunnels. It also gives a brief overview of the situation regarding this issue in other member states in Europe.(*) The Tunnel Studies Centre (CETU) is the central technical service of the Ministry of Ecology, Sustainable Development, Transport and Housing responsible for all the technical aspects of tunnels. CETU is attached to the Directorate General for Infrastructure, Transport and the Sea and is involved in all stages of tunnel engineering works from design to asset management, as well with facilities and civil engineering issues.^p

Design of Mountain Road Tunnel Safety Monitoring System

The tunnel, the construction safety of which is the most important part of highway to put into operation in time, is an important part of the mountain region road. Based on the characteristics of New Austrian Tunneling Method, the importance of safety monitoring system for grasping the rock deformation in the construction process goes without saying. This paper presents a safety monitoring program through the construction of the sage Mei Shan Highway, Lung Hang Tunnel, providing theoretical and operational support for the sage Mei Shan Highway through analyzing the construction process, the principle of safety monitoring, frequency of monitoring items, monitoring and early warning system, measures to ensure measurement accuracy, measurement data analysis, feedback of early warning system.

Photocatalytic performances in a city tunnel in Rome: NO x monitoring results

This paper deals with the results of two environmental monitoring campaigns entailing the analysis of NO x levels registered before and after the renovation work of the “Umberto I” tunnel in Rome, Italy. The results of the data collection highlighted an efficient abatement of pollutants by the photocatalytic treatment of the tunnel vault with a cement-based paint, as evidenced through the lower concentrations found after the renovation. A NO x reduction of about 20% was calculated in the center of the tunnel (as an absolute comparison between the two periods), whereas a NO x reduction of over 50% was calculated in the same position, considering the reference data registered in the official stations of the city of Rome (Official Environmental Agency – ARPA). The duration of the monitoring campaigns performed seems to be considered significant from the statistical point of view, unlike all previous experiments which were carried out on the photocatalytic materials. This renovation project can prove out to be a very useful reference for the wide program for a sustainable upgrading of tunnels in Europe, according to the Directive 2004/54/EC on road tunnel safety.

Use of analytic hierarchy process and fire dynamics simulator to assess the fire protection systems in a tunnel on fire

The road and rail tunnels are increasing in number. Corresponding to this higher number of tunnels, a higher number of accidents related to safety problems occur. The safety of road and rail tunnels is mostly related to fire safety. Our purpose in this paper is to present a new integrated approach to the analysis of fire safety in tunnels. Using different techniques from the decision support tools, such as the analytic hierarchy process, and through the use of a fire dynamics simulator, we suggest a new priority in the classification of the fire-fighting systems in tunnels. Attention will be paid especially in the analysis of the ventilation systems in tunnels.

New methods for road tunnel fire safety evaluation and upgrading

A new tunnel fire safety evaluation and upgrading procedure was developed to replace the current seriously flawed ‘additive’ methodology. Such a procedure is necessary given the number of recent tunnel fires with serious consequences to human life, structure and the wider socio-economy. The procedure takes a holistic integrated approach and follows a critical path. The new methodology, called Upgrade, was tested for a hypothetical ‘basic’ example tunnel and showed its ability and flexibility in providing the risks and economic impacts for different upgrading options singly and in combination. The assessment shows clearly that it is not just safety features that are critical to results but also items such as the location of the fire and its size. The model is also applied to a ‘real’ alpine tunnel case to demonstrate that the smoke extraction system would have been justified by the holistic upgrading procedure. Both the development of Upgrade and the appraisal of socio-economic impact are key innovations of this work. Tunnel closure times were found to have a marked, even dominant, influence on human safety and especially the socio-economic impact. Closure times should therefore be reduced to a minimum by judicial selection of a combination of safety features that require night closures or part closure coupled with a reduced overall time for upgrading work. The work was carried out as part of the Uptun (Upgrading tunnels) 5th framework European Union (EU) project. The results of this work are aimed at assisting the EU develop a directive for road tunnel safety.

M25 Holmesdale tunnel – setting a new standard for safety

Following a spate of fatal fires in European motorway tunnels, new EU road tunnel safety legislation was enacted in the UK in 2007. One of the first tunnels to be brought up to the new safety standards was the 25-year-old, 650 m long Holmesdale tunnel on the M25 motorway north of London – one of the busiest in Europe with up to 120 000 vehicles a day. This paper reports on the planning, procurement and management of the tunnel’s recent £75 million refurbishment, which included replacing all mechanical, electrical, operational and communication systems and installing passive fire protection – and all without closing the tunnel to traffic. The award-winning scheme was completed three months early, on budget and without a single reportable construction accident.

Optimization of Road Tunnel Safety

Probabilistic methods of risk optimization are applied to identify the most effective safety measures considered in design of road tunnels. The total consequences of alternative tunnel arrangements are assessed using Bayesian networks supplemented by decision and utility nodes. It is shown that the probabilistic optimization based on the comparison of societal and economic consequences may provide valuable information enabling a rational decision concerning effective safety measures. Thereby risk acceptability criteria are critically reviewed. A general procedure is illustrated by the optimization of a number of escape routes. It appears that the discount rate and specified life time of a tunnel affect the total consequences and the optimum arrangements of the tunnel more significantly than the number of escape routes. The optimum number of escape routes is also significantly dependent on the ratio of the cost of one escape route and acceptable expenses for averting a fatality based on the LQI. Further investigation of relevant input data including societal and economic consequences of various hazard scenarios as well as experience related to the effectiveness of safety systems are needed.

The Application of Risk Analysis in the Assessment and Management of Road Safety in Road Tunnels

The Application of Risk Analysis in the Assessment and Management of Road Safety in Road TunnelsRoad tunnels are highly sensitive to disturbance caused by road accidents. The most serious accidents occurring in tunnels involve trucks carrying hazardous materials. Europe has been developing methods of risk analysis and building models for traffic management in tunnels. Poland is only just beginning to build road tunnels and the area of tunnel safety has not been given adequate attention yet.

In-vehicle information systems to improve traffic safety in road tunnels

Abstract Introduction In-vehicle information systems can improve safety, improve driver’s situational awareness and reduce anxiety, but they may also increase mental workload and distraction. This issue is particularly important in road tunnels because they create extremely dangerous driving conditions. Goals To evaluate the effect of in-vehicle displays on driving safety in road tunnels, this paper address two questions: (1) can we still add information to in-vehicle displays without compromising safety? and (2) if information can still be added, how much information should added? Method We simulated tunnel driving and evaluated the effects of driving performance with innovative in-vehicle displays in terms of safety and satisfaction. We compared a highly informative display and a minimal information display with driving without a display as a control. Results Using the displays, drivers improved their speed control but had some difficulty in maintaining lane stability, apparently due to some distraction imposed by the displays. Yet, neither of them increased the mental workload relative to driving without a display. The drivers found the in-vehicle displays useful and responded well to the presented information. The drivers preferred the more informative display to the minimalist display, although it slightly increased distraction from road. Conclusions In light of the potential benefits of in-vehicle displays, the level of distraction was relatively minor and should not compromise driving safety. Apparently, the highly informative display provided drivers with more information that reduced anxiety and boredom, which are common psychological experiences during tunnel driving. Thus, safety-related information displays can be added to improve safety even when some of their benefits are offset by increased distraction.

State-of-the-art road tunnel safety

This paper presents the current state of French and European practices for road tunnel safety. It rapidly surveys the main aspects of legislation, and then presents the evolution of risk governance in tunnels from being initially focused on technical devices to gradually integrating human and organisational aspects in the approach of safety. A brief presentation of recent projects dealing with safety in tunnels is also presented, with a focus on the study of psychological aspects of users' behaviour. Experimental results are discussed.

The international FORUM of fire research directors: A position paper on future actions for improving road tunnel fire safety

Fire safety in tunnels has come in focus owing to numerous catastrophic fires and extensive monitoring in media. Casualties can be counted in hundreds and the economic damages have been enormous not only for tunnel owners but also for users and bordering communities. The recent increase in serious road tunnel fires is closely associated with the increase in the traffic volume as well as in the large number of tunnels being built in recent years. In particular, volumes transported on heavy goods vehicles have increased by 40–80% over a decade in many European countries. Today, about 75% of all goods traffic is by road, and is expected to increase by 40–60% over the next 10 years [Thamm B. The new EU directive on road tunnel safety. In: Proceedings of the international symposium on catastrophic tunnel fires (CTF), SP Swedish National Testing and Research Institute, SP Report 2004:05. p. 19–30]. This FORUM position paper discusses some aspects on how to improve the design of road tunnels in order to obtain a higher level of fire safety. It discusses briefly design principles of tunnels as well as of fire safety of vehicles, use of forced ventilation systems and of active fire suppression.

The Mrázovka tunnel in Prague before completion

Prague, the capital of the Czech Republic, lies in the heart of Europe. It is exceptional not only by its beauty, but also due to the fact that the planned system of main urban roads has not been completed yet. Currently the most topical issue is the Mrazovka tunnel being in the process of completing the works, with the scheduled inauguration in August 2004. The Mrazovka tunnel is 1300 m long in total. It consists of two tubes with one-way traffic (the ETT and WTT). Three-lane mined tunnels form the major part of the tunnel structure. In terms of length and cross sections, the Mrazovka tunnel tubes are the largest and technically most difficult project implemented till now in the Czech Republic using the New Austrian Tunnelling Method. The difficulty followed from the longitudinal profile of the tunnel route, the geology encountered and existence of residential buildings above the tunnels. The most difficult sections of the drive were the three-lane tubes at the portal North under Mrazovka Hill, the excavation under the buildings existing at locations with shallow rock cover, and the excavation of bifurcation chambers with a cross section up to 324 m2. The tunnel excavation and primary lining were completed in April 2002. Casting of final lining started in April 2001, the work was finished in August 2003. In terms of the approved traffic study, various profiles of the mined tunnels, i.e., profiles for three-lane and two-lane tunnels, bifurcation chambers, tunnel ramps and cross passages had to be carried out at the Mrazovka tunnel. The structural design of the final liner was significantly affected by the longitudinal profile of the tunnel too. It called for application of a closed waterproofing system and for the liner proportioning counting with a full hydrostatic head from groundwater level found up to 30 m above the tunnel crown. The waterproofing is provided along the entire circumference of all mined profiles. In terms of structural analysis the most interesting were the design of final lining of the three-lane tunnel with the slab under the roadway participating in a composite action with the liner as a tension member, and the design of final lining for a bifurcation chamber having an internal width and height of 20.5 and 11.4 m, respectively. The original design of equipment for the Mrazovka tunnel was elaborated in compliance with recommendations and conclusions of the PIARC conferences held in Marrakechi in 1991 and in Montreal in 1995. At the time when the design had already been completed, the contractor selected, and civil and mining work on the Mrazovka tunnel started, the opinion on the active and passive operational safety in road tunnels changed substantially all over the world. This change took place in the nineties, after several conflagrations in tunnels with catastrophic consequences. For the above reason the already designed Mrazovka tunnel equipment had to be redesigned. The new system designed was based on the requirement for intensive evacuation of smoke from the fire vicinity, within a length of about 400 m. The PIARC recommended suction performance for a three-lane tunnel was 120 m3/s in 1999. Functionality of the newly designed system was verified by mathematical and physical modelling. A study on operational safety in tunnelled sections of the City Ring Road in Prague was developed in 2002, using acknowledged world-wide parameters. It proved that the operating Strahov tunnel, Zlichov tunnel, the Mrazovka tunnel being currently completed, and the other three tunnels on the City Ring Road being designed, satisfy the operational safety requirements. Currently the Mrazovka tunnels are in the phase of equipment installation. The required term of bringing the Mrazovka tunnel into service is August 2004. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Latest achievement and perspectives in tunnel safety

Through a tragic series of accidents the safety in European traffic tunnels has become a much discussed issue in public. This has lead to intensified multinational efforts to improve the safety levels for tunnel users and for the structures themselves. This paper gives an overview on the latest developments for safety in road tunnels by presenting: Background information on traffic development and the resulting need for underground solutions; Case information and statistics on fire accidents in tunnels; An analysis of the effects of fire in traffic tunnels; A description of the state-of-the-art in fire protection measures; Important hints on how to behave when driving through a road tunnel; A summary of the research and development activities supported by the European Commission. Various forecasts for the development of traffic in Europe over the next two to three decades have in common that a steep increase bringing European highways and other transport lines to the limit of their capacity. Combined with the demands from a growing world population and an increasing degree of urbanisation this leads to many tunnelling activities on a worldwide scale over the next 10-15 years. High safety levels and reliable availability are essential for all these tunnels. Recent fire accidents which have caught much attention in public and general accident statistics of vehicle fires make evident the necessity for improvements of the fire protection of tunnels and of the behaviour of drivers in tunnel. Considerable progress has been made in the development of fireproof tunnel linings and operational fire protection such as improved ventilation schemes. In addition to the manner in which tunnels are furnished, improved control of the state of vehicles and the composition of their loads could better safety standards in traffic tunnels. Joint efforts are imperative to arrive at enhanced and harmonised standards throughout Europe. Comprehensive research work recently launched by the European Commission as well as organised test programs contribute significantly in this way. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Fire and life safety provisions for a long vehicular tunnel

Recent major incidents in European road tunnels such as the 12 km Mont Blanc Tunnel between France and Italy and the 17 km St. Gotthard Tunnel between Italy and Switzerland have caught world attention on safety in long road tunnels. These tragic incidents have resulted in loss of lives and severe damage to tunnel structures. Current publications on road tunnel fires also indicate that the major factors that contribute to the protection of life and property in road tunnels are safe tunnel layout, effective ventilation system, adequate safety equipment, good incident response strategies, proper driver behaviour, and appropriate regulatory control. This paper describes the fire and life safety provisions for the Kallang/Paya Lebar Expressway which is a major expressway in Singapore providing a link between the East Coast Parkway in the south and the Tampines Expressway in the north. It is a complex project made up of tunnels, slip roads, viaducts, open expressways and ventilation buildings. It has a total length of 12 km of which approximately 8.7 km is in tunnel. The Expressway tunnel is linked to eight entry and nine exit slip roads and will be one of the longest dual 3-lane road tunnels in Southeast Asia when completed in 2007. As the Expressway tunnel is designed as a heavy traffic urban road tunnel, it is essential that there are adequate fire and life safety provisions to allow early warning and detection of incidents, safe evacuation of motorists, and rapid access to the incident site by emergency services. This paper addresses the major fire and life safety provisions in the Kallang/Paya Lebar Expressway tunnel including: (a) Tunnel and slip road layout (b) Means of escape (c) Construction material and structural fire precautions (d) Emergency ventilation system ( e) Safety equipment and tunnel systems (f) Incident management and responses (g) Emergency services (h) Regulation and enforcement (i) Driver behaviour and awareness. Each of the above factors will contribute to the total solution of fire and life safety in the tunnel. This paper describes the design objectives of fire and life safety provisions, how each of the provisions was considered and how they were co-ordinated to form integrated emergency procedures and fire fighting strategies for the Operator and the emergency services. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

State of the road tunnel safety technology in Japan

As more and more tunnels have been constructed to develop new road network, through mountainous ranges or to avoid environmental problems in urban areas, safety in road tunnels has been becoming a major issue. Establishment of tunnel safety measures is the most important task for all those who are engaged in road tunnel design, construction, operation or safety. Based on the past experiences of serious accidents involving fires, efforts to improve safety in road tunnels have been made by establishing technical standards with technological progress and improving emergency facilities in Japan. This paper describes the state of the road tunnel safety technology in Japan.

Tunnel fire and life safety within the world road association (PIARC)

This paper presents the global activities of the World Road Association (PIARC) in the area of fire and life safety in road tunnels. It traces the organizational structure in the form of technical committees, its publications, current activities and concludes with a summary as to the position of the organization with regard to fire and life safety in tunnels.

Fire safety: a short history in the Paris subway

After a short presentation on the Paris Transport Authority (RATP), this paper describes the evolution of the objectives of the use of the natural and mechanical ventilation system during the last 30 years. According to the different regulations and guidelines used for safety in road and rail tunnels in the world, it shows the methodology used and the difficulties in defining an optimized system for cost and efficiency.