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

Tunnel

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 built underneath Downtown Phoenix

Downtown Phoenix

Downtown Phoenix is the central business district of Phoenix, Arizona, United States. It is located near the geographic center of the Phoenix metropolitan area or Valley of the Sun. Phoenix, being the county seat of Maricopa County and the capital of Arizona, serves as the center of politics,...

. It was built as part of Interstate Highway 10

Interstate 10 in Arizona

In the U.S. state of Arizona, Interstate 10, the major east–west Interstate Highway in the southern United States, runs east from California, enters Arizona and continues through Phoenix and Tucson and exits at the border with New Mexico.-Route description:...

 in Phoenix, Arizona

Phoenix, Arizona

Phoenix is the capital, and largest city, of the U.S. state of Arizona, as well as the sixth most populated city in the United States. Phoenix is home to 1,445,632 people according to the official 2010 U.S. Census Bureau data...

.

Route

The tunnel extends from approximately North 3rd Avenue to North 3rd Street. At 2,887 feet (879.95m), it ranks as the 42nd longest vehicular tunnel in the US

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. The tunnel 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.

Margaret T. Hance Park

Above the tunnel exists a park that was named after former Phoenix Mayor Margaret Taylor Hance

Margaret Hance

Margaret Taylor Hance was the first female mayor of Phoenix, Arizona, taking office in 1976. She proved popular, winning four consecutive two-year terms, from 1976 to 1983.-Biography:...

 a few months after her passing in 1990. During her mayorship, Hance was a strong proponent of the tunnel and the park.

Design

The tunnel, which is more of a "table" design rather than an actual 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. Between the two tubes exists a single-lane tube that was designed as an express terminal for city buses. The tube is unused, and the approaches on both sides of the tunnel are gated off.

Ventilation and Equipment

The Deck Park Tunnel was designed to be ventilated naturally, using the car's energy to help propel air through the tubes. In times of heavy traffic or in the event of a fire in the tube, each tube has four backup fans that provide ventilation, in order to prevent the dangerous buildup of carbon monoxide

Carbon monoxide

Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...

.

The tunnel has a large diesel generator approximately 50 meters east of the westbound entrance to the tunnel, ensuring that the lighting

Lighting

Lighting or illumination is the deliberate application of light to achieve some practical or aesthetic effect. Lighting includes the use of both artificial light sources such as lamps and light fixtures, as well as natural illumination by capturing daylight...

, video surveillance

Closed-circuit television

Closed-circuit television is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors....

, and intercom

Intercom

An intercom , talkback or doorphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles...

s have continuous power even during an outage. For the safety of motorists, intercoms are located every 150 feet (45.7 m) within the tunnel.