Case Studies

Tunnel information
System: Bidirectional tunnel
Length: 1,300 m
AADT: 25,000 vehicles/24 h

Type of work
Existing tunnel equipment does not comply with guidelines
Guidelines require four emergency exits and costly smoke extraction
Review whether equal or lower risk can be achieved by using mechanical longitudinal ventilation and providing additional emergency exists

Measures
Variable number of emergency exits (none, four and nine emergency exits)
Different ventilation systems (smoke extraction, mechanical longitudinal ventilation)

Risk model Germany

Tunnel information
System: Bidirectional tunnel
Length: 4,300 m
AADT: 19,000 vehicles/24 h

Type of work
Bidirectional traffic in tunnel is to be maintained during rehabilitation
Guidelines require costly smoke extraction
Identification of innovative measures to achieve lower risk compared to reference tunnel even with mechanical longitudinal ventilation

Measures
Speed limit of 60 km/h
Speed monitoring with section control
Fire brigade on stand-by duty at the tunnel portals
Combination of several measures

Risk model Austria

Tunnel information
System: Bidirectional tunnel
Length: 1,500 m
AADT: 13,000 vehicles/24 h
Percentage of busses: 7 %

Type of work
Guidelines require costly smoke extraction
Provision of emergency exits very costly due to location
Identification of innovative measures to achieve lower risk compared to reference tunnel even with mechanical longitudinal ventilation

Measures
Variable number of emergency exits (none, two emergency exists)
Different ventilation systems (smoke extraction, mechanical longitudinal ventilation)
No busses
Automatic fire-fighting system
Neutral ventilation (zero-flow ventilation)
Combination of several measures

Risk model Austria

Tunnel information
System: Unidirectional tunnel
Length: 1,700 m
AADT: 86,000 vehicles/24 h

Type of work
Determination of appropriate tunnel cross section for new tunnel
Review of impact of long arrival times of fire brigade
Representation of impact of additional emergency lane

Measures
Different tunnel cross sections (standard cross section 33t/33T/36t+, rectangular/vault)
Different arrival times of fire brigade (15 min, 23 min)

Risk model Germany

Tunnel information
System: Bidirectional tunnel
Length: 5,000 m
AADT: 11,000 vehicles/24 h

Type of work
Existing tunnel equipment does not comply with guidelines
Evaluation of possible alternatives

Measures
Local Speed Control (LSC)
Section Control (SC)
Distance Control by LEDs (DC)
Thermal Scanner (TS)

Risk model Slovakia