The Papago Freeway Tunnel, better known to Phoenix residents as the Deck Park Tunnel, is a vehicular

underpass A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube constr ...

built underneath

Downtown Phoenix Downtown Phoenix is the central business district (CBD) of the City of Phoenix, Arizona, United States. It is located in the heart of the Phoenix metropolitan area or Valley of the Sun. Phoenix, being the county seat of Maricopa County, Ari ...

. It was built as part of Interstate Highway 10 in

Phoenix, Arizona Phoenix ( ; nv, Hoozdo; es, Fénix or , yuf-x-wal, Banyà:nyuwá) is the List of capitals in the United States, capital and List of cities and towns in Arizona#List of cities and towns, most populous city of the U.S. state of Arizona, with 1 ...

Route

The underpass extends from approximately North 3rd Avenue to North 3rd Street. At , it ranks as the 42nd longest vehicular tunnel in the United States. The underpass was the last section of Interstate 10 to be completed nationwide. There is a plaque dedicated to the commemoration of the tunnel in Margaret T. Hance Park, which sits above the structure.

History

Voters in Arizona voted down a similar plan to build the tunnel in 1975, after voting down a proposal for a raised highway through Downtown Phoenix in 1973. Plans for the Deck Park Tunnel were finally approved by voters in 1979, and construction began in 1983. The tunnel was opened to traffic on August 10, 1990, following a three-day open house that attracted 100,000 people.

Design

ADOT The Arizona Department of Transportation (ADOT, pronounced "A-Dot") is an Arizona state government agency charged with facilitating mobility within the state. In addition to managing the state's highway system, the agency is also involved with pu ...

officials concede the term "tunnel", in this case, is a misnomer, because it is actually a series of 19 side-by-side bridge underpasses. The term, however, is now deeply rooted in local vocabulary. The bridges over the tunnel are about to long. The tunnel is divided into two tubes, each carrying five lanes of one-way traffic flanked by two emergency lanes. Each of the two tubes can carry up to 16,000 vehicles per hour.

Unused bus lanes

Between the two tubes exists a tube containing two lanes, designed as an express transit terminal for city buses. The terminal was originally planned to be built next to the Central Avenue bridge over Margaret T. Hance Park. Passengers disembarking at the terminal will take an

escalator An escalator is a moving staircase which carries people between floors of a building or structure. It consists of a motor-driven chain of individually linked steps on a track which cycle on a pair of tracks which keep the step tread horizo ...

or an

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

to the surface, and continue their journey. While the bus lanes were built, the City of Phoenix was unable to secure the over $20 million needed in

Federal Government A federation (also known as a federal state) is a political entity characterized by a union of partially self-governing provinces, states, or other regions under a central federal government (federalism). In a federation, the self-governin ...

funds to complete the project. The tube is currently unused, and the approaches on both sides of the tunnel are gated off.

Ventilation and equipment

In times of heavy traffic or in the event of a fire in the tube, fans can be started up to provide ventilation, in order to prevent the dangerous buildup of

carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...

. There are eight fans and four fan rooms, and each fan can run anywhere from 250 to 700 horsepower. The fans are automatically turned on when air sensors in the tunnel are triggered, and can replace the tunnel's air in less than five minutes. The underpass has a large diesel generator approximately east of the westbound entrance to the tunnel, ensuring that the

lighting Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylig ...

video surveillance Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly tr ...

, and

intercom An intercom, also called an intercommunication device, intercommunicator, or interphone, is a stand-alone voice communications system for use within a building or small collection of buildings which functions independently of the public telephon ...

s have continuous power even during an outage. For the safety of motorists, emergency telephone cabinets are located every within the tunnel.

References