It’s probably safe to say that the majority of Pittsburghers have spent a whole lot of time waiting in traffic to go through the city’s tunnels then zipping through, only to sigh with relief when we see daylight again. However, how many of us have ever stopped to think about the history behind those tunnels? The longest tunnel in Pittsburgh, for example, boasts a pretty fascinating history.

At just over a mile in length, the Liberty Tunnel earns props as the city’s longest tunnel, shuttling traffic along on its four lanes from downtown Pittsburgh to South Hills.

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The tunnel dates back nearly a century, opening in March 1924, before the entire construction process was even complete. That’s where the tale of a near-tragedy begins.

Wikimedia Commons/Public Domain

A ventilation system had already been designed for the tunnel. However, the tunnel opened before that ventilation system had been installed. Experts figured travelers would be safe, because…

Wikimedia Commons/Public Domain

They would just drive through the tunnel, which would push the fumes out of the tunnel. Unfortunately, experts didn’t take into account the possibility of a traffic jam.

Flickr/Jon Dawson

May 10, 1924, tested the theory that not having a ventilation system would be safe. The roads were jam-packed since there was a strike by public transportation workers.

Flickr/Jon Dawson

An inevitable traffic jam resulted, leaving cars stuck both outside and inside of the Liberty Tunnel. Drivers were ordered to turn off their cars to stop the build-up of carbon monoxide.

Flickr/Friscocali

Unfortunately, some of those stuck in the tunnel passed out from the dangerous fumes with others desperately running for the exit. No one died as a result of the incident.

Flickr/Doug Kerr

It took another year for the ventilation system to be installed in the Liberty Tunnel.

Flickr/Stevie Rocco

Today, the Liberty Tubes connect thousands of drivers from the city to the south suburbs, and vice-versa, each day.

Flickr/Doug Kerr

Did you know the Liberty Tunnel is the longest tunnel in Pittsburgh? If you’re a fan of bridges, plan a day trip to Herline Covered Bridge in Bedford County.

Wikimedia Commons/Public Domain

Flickr/Jon Dawson

Flickr/Friscocali

Flickr/Doug Kerr

Flickr/Stevie Rocco

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Address: Liberty Tunnel, Pittsburgh, PA, USA