Technological advances have improved the ability to monitor, control and manage operational and safety performance of transit systems. However, they have significantly added to the complexity of projects, particularly tunneling projects. For example, a transit line project can have thousands of unique communications points that are transmitted and report in some manner to a remote location, such as a control center. These include train tracking, signaling, emergency communications devices, intrusion alarms, gas monitors, failure monitors on myriad types of equipment, ventilation control and monitoring, fire alarms, and CCTV.
While not expensive as stand-alone elements, their installation, integration, and testing can add significant time to rail projects. Many of these subsystems, like fire alarms, must be connected in order to work. Activation of a fire alarm in a station affects operational functions of elevators, escalators, messaging systems, station ventilation and alarm reporting. Each interface must be tested for each alarm, of which an underground station can dozens.
Further, given the long time to complete rail projects, specifications for advanced communication systems are often obsolete by the time they are ready to be installed toward the end of a project. This can result in change orders with schedule impacts if upgrading to a more modern standard. Many of these technological requirements are driven by fire and safety codes that are unique to rail projects, discussed in detail below.
Fire Safety Standards
Rail transit stations, particularly below ground, are also subject to safety regulations. The U.S.-based National Fire Protection Association (NFPA), an independent global trade group, publishes safety and fire codes for a range of facilities, including rail transit systems under NFPA 130 Standard for Fixed Guideway Transit and Passenger Rail Systems.258 NFPA 130 is not federal law, but it has been formally adopted by many jurisdictions and agencies as part of their fire safety codes for rail transit construction. While some countries like Spain, France, Japan, Italy, Germany and Austria have their own fire safety standards for transit, most agencies around the world follow NFPA 130.259
NFPA 130 largely consists of performance-based criteria for ventilation, fire endurance and spread, and evacuation, but also include specific provisions for materials, distances between exits, spacing of stations and cross-passageways, and doors, among others. For example, one part of the code that has direct implications for the scope of subway stations, and thus costs, is riders standing on a platform must be able to evacuate the station within four minutes and reach a safe location within six minutes.260
The code also sets parameters for modeling evacuation scenarios. These evacuation times are based on peak service, with trains one headway behind schedule, resulting in twice the normal passenger load on vehicles and twice as many passengers on a platform.261 Additionally, evacuation scenarios assume that one escalator on each station level is out of service, and that the escalator chosen must be the one that would most negatively impact passenger exit capacity.262 Escalators generally cannot make up more than half of a station’s egress capacity on each level.263 This is intended to ensure that evacuation can be completed even in a worst case scenario.
One of the more significant determinants of station platform size are NFPA 130 requirements on the number and width of stairs, as well as the maximum permissible distance from the most remote points of the platform to the nearest exit.264 As a result, station and platform sizes often comfortably exceed the levels that would be necessary to handle normal passenger flow rates. While intended to ensure space for evacuation, meeting these strict standards can lead to a more comfortable passenger experience.265
Other standards that may impact station costs or elements include provisions for the inclusions of cross-passages to allow for passengers to move between tunnels in case of emergency and, for example, if one tunnel has smoke. According to NFPA 130, if the distance between two stations is greater than 2500 feet, cross passages must be built between the tunnels at 800-foot intervals if there are no intermediate shafts to the surface.266 According to one analysis, cross passages are rare in Europe as well as in Japan.267 This is likely in part due to the relatively close spacing an d travel time between stations that may allow passenger to walk a short distance to evacuate, and reducing the likelihood that a train would get caught in the middle of a tunnel and unable to drive to the next station.268 Constructing cross-passages can require additional excavation and complexity that may affect construction costs.
Ventilation systems that can bring fresh air to underground passengers during a safety incident is also a major element of underground metro systems. NFPA 130 requires mechanical and passive ventilation systems to become fully operational within 180 seconds, and maintain airflow rates for at least one hour to allow for evacuation of vehicles.269 Design of ventilation systems also accommodate the maximum number of trains possible between ventilation shafts during an emergency.270
Transit systems in earthquake prone areas also must comply with seismic safety guidelines. At and above ground systems are particularly vulnerable to ground movement from earthquakes while underground transit systems largely move with soil in the event of an earthquake and are generally safer.271
Seismic codes for transit are largely handled at the local or a gency level, though there are certain statewide and federal guidelines that agencies may incorporate into their design standards.272 For example, Seattle’s Sound Transit adopted agency-wide seismic standards that take a hazard-based approach to earthquake resilience. These approaches include planning for an Operating Design Earthquake (ODE) this strength over a facility’s 100 year design life. The other is a Maximum Design Earthquake (MDE), which would be expected to occur once every 2500 ye ars, with a 4 percent chance of an earthquake exceeding this level during a facility’s design life. Sound Transit’s guidelines require light rail facilities to withstand ODE’s and resume operations in a “reasonable amount of time,” and withstand a MDE without collapsing or risking lives.273
Meeting such standards can vary depending on the seismic profile of varying regions. For example, San Francisco’s Bay Area Rapid Transit (BART) strengthened its standards over the past decades and are undertaking vulnerability analyses and retrofitting key facilities to enhance their earthquake resilience. These measures include enlarging tunnels that cross through faults to account for potential displacement and incorporating concrete-encased steel ribs.274 Aerial structures are reinforced with stronger foundations or columns to withstand collapse or poor soil is replaced with non-liquifiable soil to prevent collapse or damage.275
Transit stations are also subject to accessibility requirements under the Americans with Disabilities Act of 1990 (ADA). Design specifications for accessibility are outlined under Title II and III of the ADA, also known as ADA Accessibility Guidelines. Enforced by both the federal departments of Justice and Transportation, these guidelines cover vehicles, buildings, transportation facilities, and many other types of facilities. The U.S. Access Board, a federal government agency, writes all code/guidance and has issued supplements to cover different facilities. The ADA guidelines were last updated in 2004 to address usability and format issues, as well as cover new types of facilities. The U.S. DOT formally adopted these new standards in 2006.
Among the DOT-specific guidelines for transit include locating accessible routes in the same area as general circulation paths, including detectable warnings on curb ramps and along platforms that do not have screen doors or platform guards, minimum platform heights, and maximum rail platform slopes.276 DOT has added to these standards over time. For example, in September 2011, DOT added a provision mandating that individuals with disabilities, including wheelchair users, “must have access to all accessible cars available to passengers without disabilities in each train using the station”, to prevent segregating disabled riders in separate vehicles.277 These standards apply to all new construction, as well as alterations to existing facilities.
The ADA requires that any alterations to existing facilities make them fully ADA compliant, or to the maximum extent feasible in cases where full accessibility is not possible. If making a facility fully accessible would exceed 20 percent of the alteration cost, agencies are only required to incorporate accessibility elements that would not result in a disproportionate cost (under 20 percent).278
A U.S. DOT 2016 ruling clarified that any alterations to existing transportation facilities that can impact their usability must incorporate accessibility, including for wheelchair users.279 The ruling also clarifies that the ADA requirement to incorporate accessibility to the maximum extent possible is primarily intended for rare cases where it is impossible to make an existing facility fully ADA compliant. In these cases, agencies cannot cite disproportionate cost as a limiting factor preventing incorporation of accessibility. The disproportional cost provision applies only in instances where a primary function area of a station (such as a platform) is being renovated.
Coverage of the impact of ADA compliance on construction costs has largely revolved around elevator retrofits on older subway systems. The cost of retrofitting elevators has gained particular attention in New York City. Only 23 percent of New York MTA’s subway stations are accessible, and the agency has retrofitted several stations without installing elevators or ramps.280 A 2019 lawsuit ruled that the agency violated the ADA by not installing elevators as part of a 2013 subway station renovation in the Bronx, and must make stations accessible when renovating future stations.281 The agency announced a $5.5 billion capital program in 2019 to install elevators in 70 stations in five years.282 The plan received increased scrutiny for its cost—nearly $78 million per elevator, in contrast to examples from European cities, where station upgrade costs per elevator are as low as $22 million.283 These costs are also lower in other North American cities like Boston, where the MBTA installed three new elevators and two escalators at a Red Line station for $36 million, and Chicago, where a new station with four elevators cost $75 million ($19 million per elevator).284
Accessibility regulations abroad are largely handled at the country level, but generally all stations built in recent decades are designed to be accessible. Transportation systems in Canada are governed by the newly enacted Accessible Transportation for Persons with Disabilities Regulations (ATPDR), as well as the 2018 Accessible Canada Act, which is the first nationwide accessibility act.285 Provinces also have their own accessibility regulations that apply to public entities, like the Accessibility for Ontarians with Disabilities Act.286 Public transportation in Australia is similarly governed by the national Disability Discrimination Act of 1992, which includes design and service standards for public transport similar to the ADA.287
There are no European Union-wide accessibility standards comparable to the ADA, but rather individual member state regulations. The European Accessibility Act, passed by the European Parliament in 2019, largely focuses on fare payment systems and does not explicitly address system design.288 Accessibility on European transit systems can vary significantly. In Barcelona, 143 out of 158 metro stations (81 percent) are accessible, while just under 20 percent of stations on the London Underground are accessible.289 Just three percent of stations on the Paris Metro, for example, are accessible to passengers with disabilities, while the much newer tram system is fully accessible.290 While France passed a law in 2005 to improve accessibility in public spaces, Paris’ Metro was exempt, and its operator has argued that the system’s age would make retrofitting stations extremely costly.
Design and architecture can be significant cost drivers for transit projects in three ways: poor management of the design processes, project design itself, and design standards. Lack of oversight of the design process can result in accepting inadequate or faulty designs that result in issues during construction and require change orders. The design of transit projects themselves, particularly on underground stations, can also raise construction costs. Deep, extravagant stations and the use of bespoke materials have been cited as major cost drivers in cities like New York and Toronto. Lastly, select safety standards can require more complex system design to make a project resistant to natural disasters like earthquakes. Stringent evacuation standards in fire safety codes like NFPA 130 can also result in large subway s tations, while the need to install cross-passages and ventilation systems can be an additional source of costs. Accessibility standards, on the other hand, do not appear to be a particularly significant cost driver for new construction, though accessibility retrofits of older station in New York City have received scrutiny for th e high costs of elevator installations compared to other cities.