ROAD TUNNELS – SAFETY AND OPERATIONS | INSIGHT
S – Safe Safety is achieved through automated monitoring and emergency response technologies. SMART tunnels use both traditional and advanced incident detection systems to identify hazards quickly and initiate an appropriate response. Examples include: ● Acoustic incident detection systems ● Thermal imaging cameras ● Linear heat detection systems ● Video analytics.
These technologies can detect incidents within seconds
and automatically trigger response procedures, reducing response times and improving safety for motorists and emergency responders.
M – Maintainable SMART tunnels are designed to reduce downtime and simplify maintenance. Sensors continuously monitor equipment conditions including vibration, temperature, airflow and overall system health. These data are analysed to identify trends and predict potential failures before they occur. Maintenance teams can then prioritise repairs, schedule work more effectively and avoid unexpected outages. A common example is tunnel lighting. In the past, lighting levels were adjusted by turning groups of high-pressure sodium fixtures on or off. Today, LED lighting systems automatically adjust brightness based on outdoor daylight conditions, reducing energy consumption. Modern lighting systems also use photometric sensors
to measure actual light levels within the tunnel. By comparing measured performance to established aging curves, operators can determine when fixtures need additional power adjustments or replacement. This approach extends asset life while maintaining compliance with lighting requirements.
A – Accessible Accessibility in SMART tunnels extends beyond physical accommodations. Modern systems may include: ● Digital wayfinding systems ● Directional LED guidance ● Audio beacons ● Enhanced emergency signage.
These features help all users navigate the facility safely
during both normal operations and emergency situations. Wayfinding during smoky conditions provides improved motorist safety.
R – RESILIENT As severe weather events become more frequent, resilience has become a critical design objective. SMART tunnels improve resilience through: ● Automated drainage controls ● Real-time flood monitoring ● Upstream rainfall monitoring ● Integrated fire and spill management systems.
These systems can detect changing conditions, respond
automatically and protect critical tunnel infrastructure while helping maintain safe operations.
T – Technology-Driven Technology serves as the foundation of the SMART tunnel concept. Key technologies include:
● Artificial intelligence (AI) ● Advanced Traffic Management Systems (ATMS) ● Supervisory Control and Data Acquisition (SCADA) systems
● Digital twins ● Automated incident detection.
Together, these technologies create a highly
instrumented operating environment that supports traffic management, structural monitoring, maintenance planning and emergency response.
FIRE AND LIFE SAFETY SYSTEMS NFPA 502 establishes the Fire and Life Safety requirements for road tunnels in the US. These systems are designed to work together as an integrated safety network. As technology advances, many tunnel systems are becoming increasingly automated. For example, a fire detection event may automatically trigger tunnel ventilation, activate traffic control measures, notify operators and alert emergency responders simultaneously. In addition, dry standpipe can be automatically filled on alarm, positive alarm sequences initiated. The specific requirements of NFPA 502 are largely
based on tunnel length. Depending on the facility, required systems may include: ● Traffic management systems ● In-tunnel traffic control systems ● Standpipe systems ● Tunnel ventilation systems ● Emergency lighting ● Wayfinding lighting ● Emergency egress facilities ● Cross-passage doors in longer tunnels.
The standard also provides guidance for fixed fire-
fighting systems (FFFS) such as deluge and water mist systems, although these systems are not mandatory. In practice, many modern tunnel projects now incorporate either deluge or water mist protection as part of their overall Fire and Life Safety strategy and, in fact, these systems provide a remote mechanism for addressing a fire event early and effectively.
TECHNOLOGIES BEYOND CURRENT NFPA REQUIREMENTS
Acoustic Incident Detection Although acoustic incident detection has not yet been widely deployed in the US, the technology has been used in Europe for more than two decades. During that time, AI-based acoustic analytics have been extensively trained to identify sounds associated with incidents and emergencies. Several US projects are now adopting
October 2026 | 25
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45
