TRANSPORT | TUNNEL LIGHTING
maintenance, reduce inspection burden through continuous status reporting, and still guarantee a reliable, intelligible egress path when everything else has already gone wrong. Lighting and controls are no longer separable line items – they are the same procurement.
Another view along Rutgers Tunnel
DUAL-USE LIGHTING - NOW PART OF THE DESIGN PROBLEM A growing number of tunnel owners are no longer procuring one system for maintenance and another for emergency egress. They are asking the same lighting backbone to support OSHA-level work illumination during outage windows and code-compliant emergency lighting during loss-of-normal-power events. That choice depends on a control system. Without one,
the two duty cycles cannot be coordinated; with one, the same fixtures can be commanded to higher output for crews, throttled back for service hours, and held at NFPA 130 levels under emergency conditions, all while reporting their own state. That changes the engineering question. The issue is no longer simply whether a fixture can deliver 0.25 foot-candles for one hour. It is whether the controls, monitoring, and lighting platform can together provide meaningful visibility for crews when the tunnel is under
REFERENCES
● [1] NFPA 130, Standard for Fixed Guideway Transit and Passenger Rail Systems.
nfpa.org/codes-and-standards/nfpa-130-standard-development/130
● [2] NFPA 101, Life Safety Code, §7.9 (Emergency Lighting).
nfpa.org/codes-and- standards/nfpa-101-standard-development/101
● [3] OSHA 29 CFR 1926.56, Illumination Standards for Construction.
osha.gov/ laws-regs/regulations/standardnumber/1926/1926.56
● [4] FTA Report No. 0232, Research Report and Findings: Emergency Egress in Rail Transit Tunnels (October 2022), commissioned in response to NTSB recommendation R-16-02.
transit.dot.gov/sites/fta.dot.gov/files/2022-10/ FTA-Report-No-0232.pdf
● [5] Commission Regulation (EU) No 1303/2014, Safety in Railway Tunnels TSI.
eur-lex.europa.eu/eli/reg/2014/1303/oj/eng
● [6] PIARC, Road Tunnels Manual: Evacuation Aids.
tunnelsmanual.piarc.org/en/ equipment-systems/evacuation-aids
● [7] BS EN 1838:2024, Lighting Applications: Emergency Lighting (standard explicitly excludes road tunnels). British Standards Institution.
bsigroup.com
● [8] National Renewable Energy Laboratory, Energy Storage Safety.
nrel.gov/ transportation/energy-storage-safety
● [9] Swedberg, C. (2021) ‘New York Subway Tunnels Leverage IoT for Emergency Lighting Connectivity’, RFID Journal, Dec 10, 2021,
rfidjournal.com/news/ newyorksubwaytunnels/193126/
● [10] Gateway Program, Hudson Tunnel Project.
gatewayprogram.org/hudson- tunnel-project.html
WHAT A MODERN SPECIFICATION SHOULD LOOK LIKE None of those decisions live in isolation. They show up in the procurement specification, or they get deferred to the bidder, which is usually where good intentions quietly disappear. Practical questions for agencies developing or evaluating tunnel emergency lighting specifications include: ● Thermal design – Has the fixture and battery system been tested at the actual sustained ambient temperature of the tunnel, not at a surface-rated maximum?
● Field serviceability – Can a single technician replace a driver or battery during a normal access window without specialised tooling or extended outages?
● Battery and backup architecture – Is backup power distributed at the fixture or centralised in equipment rooms? What does the chosen chemistry do at end of life, and what does it do under fault? Is that consequence acceptable in this tunnel, with this ventilation capacity?
● Verification and controls – Does the system report its own status, battery condition, and fault state without sending a person to each fixture? Can the same controls platform coordinate emergency-level output, work-zone output, and normal-service output, or is each duty cycle a separate procurement?
● Lifecycle cost – Over a 15- to 20-year horizon, what are the realistic replacement intervals, and what does it actually cost to gain access and perform that work?
● Use profile – Has the system been specified as a dual-use asset, with duty cycle, charging strategy, and control logic aligned to both emergency egress and OSHA-level maintenance lighting?
These are not manufacturer talking points. They are
engineering and procurement questions, and agencies that answer them early will get materially different outcomes than those that rely on legacy notes copied forward from the last tunnel project.
CLOSING Emergency lighting has been treated as the simplest system in the tunnel for a long time. It is not. Its weaknesses only become visible when the rest of the system has already failed, which is the worst possible moment to discover them. The technology has moved ahead. Major projects are
already treating tunnel lighting as a monitored, controllable, dual-use life-safety asset rather than a static row of fixtures. Standards will continue to evolve, but agencies do not need to wait for the next code cycle to act. The practical next step is to rewrite tunnel emergency
lighting specifications now – before the next rehabilitation package reaches design development, and before another generation of tunnels inherits yesterday’s assumptions.
34 | June 2026
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