This year was an anniversary year for the ADAC tunnel test: For the tenth time in succession the test programme was conducted by the motoring clubs and its partner clubs in Europe. In the meantime, it has become the basis and driving force behind EuroTAP (European Tunnel Assessment Programme), the programme for greater tunnel safety in Europe. In the 2008 anniversary year, 31 tunnels were tested in eleven European countries: five each in Italy, Switzerland and Spain, four each in Germany and Austria, three in Norway, two each in Andorra, Belgium, Croatia and the Netherlands, as well as the Karawanken tunnel on the border between Slovenia and Austria, which was tested this year for the fourth time after 1999, 2003 and 2005 (each time with Acceptable). This was the second round of testing for the Arlberg tunnel (1999/ Acceptable) and the Trebesing tunnel (2007/ Good) in Austria, the Waasland tunnel (2003/ Very poor) in Belgium, the San Bernardino tunnel (1999/ Poor) in Switzerland, the Universität Düsseldorf tunnel (2006/ Poor) und the Wattkopf tunnel (2004/ Very poor) in Germany, as well as the Maas tunnel (2003/ Very poor) in the Netherlands. The criteria which determined the choice of test candidates included tunnel length, the importance of the tunnel for holiday traffic and location in the Trans-European road network.
As in previous years, ADAC commissioned DMT GmbH, an international technology services company specialising in raw materials, safety and infrastructure with a staff of around 580, to carry out the test. With regard to tunnel construction, the company's services range widely from soil analysis to planning and safe operation of tunnel systems. One aspect of this work focuses on safety in complex systems, in particular, on protection against fire and explosion, as well as on ventilation and rescue services. DMT operates a state-of-the-art training centre for fire brigades where firemen are trained under realistic conditions to fight fires in tunnels and buildings.
The experts from DMT carried out their on-site inspections of the 31 tunnels between 7 January and 1 February 2008. Following inspection of the respective tube, the experts spoke with operators, clarified safety relevant issues and inspected the related documents. Prior to testing, operators were given a data list to record the most important technical tunnel parameters. This data was once again checked on site during the test. Although the retrofitting and modification plans for some of the tunnels are noted in the criticisms of the individual tunnels, these were not included in the rating.
Checklist
A checklist, which was prepared by the traffic experts at ADAC and DMT and is revised every year, served as an objective foundation for testing. The checklist is also based on the high standards for road tunnels in Germany, Austria, Switzerland, France and the UK, as well as on the EU Directive on minimum safety standards for tunnels in the Trans-European Transport Network.
The checklist is broken down into eight categories:
Tunnel system - Weighting: 14 percent
Number of tubes
Brightness of tunnel walls
Width and layout of traffic lanes
Geometry and layout of emergency lanes / lay-bys and emergency walkways
Traffic and traffic surveillance - Weighting: 17 percent
Congestion in the tunnel
Speed limits
Restrictions on and/or registration of vehicles carrying hazardous goods
Measures to close the tunnel: traffic lights, barriers, information displays
Traffic signs
Traffic management and control: traffic lights, variable traffic signs, signs
Visual guidance equipment
Video surveillance
Automatic traffic recording and detection of congestion and incidents
Tunnel control centre
Additional measures: for instance for heavy goods vehicles and automatic detection of hazardous goods transports, height checks, monitoring the distance between vehicles and speed
Communication - Weighting: 11 percent
Traffic radio
Loudspeakers
Emergency phones: distance, marking, insulation against traffic noise, functions
Tunnel radio
Escape and rescue routes - Weighting: 14 percent
Evacuation lighting and escape route signs in the tunnel
Distance between emergency exits and marking
Preventing smoke from penetrating external escape routes, fire resistant doors
External access and access for rescue services
Additional measures: special lighting for emergency exits, signs showing what to do, barrier-free emergency exits
Fire protection - Weighting: 18 percent
Fire protection of the tunnel structure
Fire resistant cables
Drainage system for draining flammable and toxic liquids
Fire alarm systems: automatic/manual
Extinguishing systems: arrangement, signs, function
Time for fire brigade to reach the tunnel, fire brigade training and equipment
Capacity and efficiency of automatic extinguishing systems
Ventilation - Weighting: 11 percent
Normal mode to thin out vehicle emissions
Control of the longitudinal flow in the tunnel and consideration of this in ventilation control
Temperature stability of facilities and equipment
Special fire programmes
Proof of correct functioning in fire trials and by flow measurements
Longitudinal ventilation: airflow speed, length of the ventilation section, airflow in the direction of traffic, reversible fans.
Transverse / semi-transverse ventilation: extraction volume flow, longitudinal flow control, opening / closing the exhaust air outlets can be controlled
Incident management - Weighting: 8 percent
Regular training for tunnel control centre staff
Maintenance plan
Emergency response plans
Automatic linking of emergency systems
Measures in the case of an accident or fire
Regular emergency drills
Safety potential
Each of the items of the checklist also has sub-items. All in all, the catalogue covers far more than 200 criteria. Each criterion is evaluated and awarded a certain number of points. The sum of these points is the result achieved for the so-called safety potential of a tunnel. It describes all the structural and organisational measures which are designed to prevent emergencies or limit their severity.
Risk potential
In addition to the above, the so-called risk potential is also calculated. This indicates not only the probability of incidents occurring, but also the possible extent of the damage. In other words, it serves as a parameter for the risk of becoming involved in an accident while driving through the respective tunnel and for the seriousness of the consequences which must then be expected. This is based on the following considerations:
The longer the tunnel, the more vehicles and hence the more people may be present in the tube. However, as the length of a tunnel increases, the fewer accidents occur.
The higher the number of HGVs, the greater the likelihood of a major fire breaking out.
If a hazardous material catches fire, this can be disastrous due to high temperatures and extremely toxic gases. This means that the unrestricted transport of hazardous goods significantly increases the risk of a major fire.
The type of traffic (unidirectional / bi-directional traffic) and traffic conditions (slow-moving traffic / congestion) influence the correct assessment of escape and rescue possibilities, as well as the choice of a suitable ventilation system. With unidirectional traffic and no congestion, longitudinal ventilation systems permit vehicles ahead of the fire zone to leave the tunnel safely. The vehicles downstream from the fire zone can be protected by extracting smoke in a single direction. In the case of bi-directional traffic or unidirectional traffic with congestion, vehicles may be located at both sides of the fire zone and may have difficulties leaving the tunnel. This places high demands on the ventilation system (suitable smoke extraction) and the design of escape routes. Furthermore, the risk of more serious accidents, e.g. head-on collisions, is greater in the case of bi-directional traffic, like the accidents that took place in 2001, for example, in the Gleinalm tunnel and the Amberg tunnel in Austria.
The longitudinal gradient of a tunnel influences smoke spread. The steeper the gradient, the stronger the thermal lift and hence the greater the zone in which smoke can spread. Furthermore, longer tunnel stretches with gradients can lead to brakes and engines overheating, particularly in the case of HGVs, and this also increases the likelihood of fire.
The risk potential is evaluated both in terms of quantity and quality. This is based on the respective analyses carried out by DMT on behalf of the Federal Highway Research Institute (BASt), as well as on the experience gained with previous ADAC tunnel tests.
The following parameters are considered for risk evaluation:
Tunnel length 1 to 6 points
Traffic volume, depending on traffic routing
Unidirectional or bi-directional traffic 1 to 10 points
Percentage of HGVs 8 points max.
Transport of hazardous goods: 5 points max.
Traffic density (vehicles per day and lane): 5 points max.
Maximum longitudinal gradient in the tunnel: 3 points max.
Additional risks, such as entrances and exits,
intersections in the tunnel or in the downstream area,
long gradients in front of the tunnel,
risk of flooding: 3 points max.
The risk points thus awarded are added together and their total is classified as follows:
Very low risk: 1 to 9 points
Low risk: 10 to 14 points
Medium risk: 15 to 21 points
High risk: 22 to 28 points
Very high risk: 29 points and higher
Overall evaluation
For the purpose of the overall evaluation of a tunnel, the safety and risk potential were brought together. The safety potential is multiplied by the tunnel-specific risk factor which is derived from the risk potential calculated. This means that it is very well possible for tunnels to be awarded a bonus, depending on their risk potential, that could significantly improve the result from the safety potential. Tunnels with a medium to low risk potential hence do not have to fulfil the same high safety requirements (safety potential) as tunnels with a very high risk potential. This complies with the EU Directive on minimum safety standards for tunnels in the Trans-European Transport Network (2004/54/EC) which makes certain safety measures contingent upon existing risk parameters.
Knock-out criteria The categories: Tunnel system, Lighting and power supply as well as Traffic and traffic surveillance are primarily preventive measures; the categories: Escape and rescue routes and Ventilation are self-rescue and rescue measures whilst the categories: Fire protection, Emergency management and Communication are measures that are needed in order gain control of an emergency.
The safety measures in the individual categories can supplement each other or compensate for each other, but can also be more or less independent of each other as, for instance, in the area of prevention. This is completely different with regard to measures for identifying and mastering certain events: Depending on the possibilities which exist to detect and report an incident, safety systems are activated either automatically or manually, adequate monitoring and control measures are taken, external services, such as the fire brigade, rescue services, police etc. can be involved. The strongest links, however, exist within and between the Escape and rescue routes and Ventilation categories. Traffic conditions (bi-directional or unidirectional traffic and congestion frequency) are very important when it comes to choosing the ventilation system, the control and monitoring of smoke extraction and the layout of emergency exits. And Serious shortcomings cannot be subsequently compensated for by other measures. For instance, missing emergency exits cannot be offset by very good lighting or a stable power supply.
In the tunnel test, this means that if a tunnel is given an overall positive rating, then ideally all eight categories of the safety potential must have a positive result, and at least none of them should be found to be very poor. Otherwise, the so-called knock-out criterion is used to lower the overall rating according to a precisely defined scheme.
On the whole, overall ratings of Very good, Good and Acceptable are in the positive range whilst Poor and Very poor are negative ratings.
The EU Directive
The EU Directive on minimum safety standards for tunnels in the Trans-European Transport Network (2004/54/EC) was adopted in April 2004. Since then, the related requirements have been integrated into the EuroTAP rating scheme. The requirements of the test were compared to those of the Directive. One difficulty here was that although the EU Directive sets forth requirements for tunnel safety, it frequently fails to specify these in greater detail. For instance, reference is made to emergency walkways, but there are no specific details concerning the minimum width and layout of such walkways (on one/both side(s)). The Directive makes no reference whatsoever to important basic criteria, such as intact road surfaces or markings, clean light fixtures or properly working emergency phones. In order to fill these gaps in the rating scheme of this test, the national laws of the most important tunnel countries in Europe were referred to.
However, the EuroTAP assessment ensures that tunnels with a medium or lower risk, which only fulfil the minimum requirements of the EU Directive, still achieve a rating of Acceptable. Since these are minimum requirements that have at times already been replaced by stricter regulations in a number of EU countries, there are still no clear limits to the performance range, and this is expressed in test ratings of Good and Very good. Tunnels with a higher risk usually have a standard of safety that is higher than the minimum requirements defined in the Directive which is why these tunnels always receive positive ratings.
EuroTAP - The Future of Tunnel Testing
the test programme was conducted by the motoring clubs and its partner clubs in Europe. In the meantime, it has become the basis and driving force behind EuroTAP (European Tunnel Assessment Programme), the programme for greater tunnel safety in Europe. In the 2008 anniversary year, 31 tunnels were tested in eleven European countries: five each in Italy, Switzerland and Spain, four each in Germany and Austria, three in Norway, two each in Andorra, Belgium, Croatia and the Netherlands, as well as the Karawanken tunnel on the border between Slovenia and Austria, which was tested this year for the fourth time after 1999, 2003 and 2005 (each time with Acceptable). This was the second round of testing for the Arlberg tunnel (1999/ Acceptable) and the Trebesing tunnel (2007/ Good) in Austria, the Waasland tunnel (2003/ Very poor) in Belgium, the San Bernardino tunnel (1999/ Poor) in Switzerland, the Universität Düsseldorf tunnel (2006/ Poor) und the Wattkopf tunnel (2004/ Very poor) in Germany, as well as the Maas tunnel (2003/ Very poor) in the Netherlands. The criteria which determined the choice of test candidates included tunnel length, the importance of the tunnel for holiday traffic and location in the Trans-European road network.
The experts from DMT carried out their on-site inspections of the 31 tunnels between 7 January and 1 February 2008. Following inspection of the respective tube, the experts spoke with operators, clarified safety relevant issues and inspected the related documents. Prior to testing, operators were given a data list to record the most important technical tunnel parameters. This data was once again checked on site during the test. Although the retrofitting and modification plans for some of the tunnels are noted in the criticisms of the individual tunnels, these were not included in the rating.
Safety potential
In the tunnel test, this means that if a tunnel is given an overall positive rating, then ideally all eight categories of the safety potential must have a positive result, and at least none of them should be found to be very poor. Otherwise, the so-called knock-out criterion is used to lower the overall rating according to a precisely defined scheme.
