Location: Squirrel Hill Tunnel in (you guessed it) Squirrel HillFeatured guests: Paul Manyisha, tunnel manager for PennDOT3 things that surprised me:1. Paul talked me through some of the landmark’s stats. The Squirrel Hill Tunnel sees more traffic than any of Pittsburgh’s other tunnels. More than 100,000 vehicles a day drive through this tunnel that opened in 1953. It’s not the oldest or newest Pittsburgh tunnel – those distinctions go to the Liberty Tunnel (opened 1924) and Fort Pitt Tunnel (opened 1960).2. There is a team of people inside the Squirrel Hill Tunnel 24 hours a day, seven days a week, says Paul. They’re ready to respond to a range of tunnel issues – from accidents to truck breakdowns to confused deer. A woman once gave birth in her car inside the tunnel. The tunnel maintainers, who are also trained first responders, were there to help in seconds.3. The 4,225 feet of tunnel wall are lined with white tiles. To keep them clean, PennDOT uses a cleaning machine that drives slowly in one of the lanes while rotating brushes scrub the walls.One thing that didn’t make the final cut: There’s a 2.5% grade incline in the tunnel, though it’s hard to notice as you’re driving through. That might explain some of the inevitable slowdowns as drivers don’t realize that they’re actually going slightly uphill when headed from east to west and fail to press the gas pedal to compensate.Additional info: This is the final installment in our Pittsburgh tunnel trilogy.Want more Yinzer Backstage Pass? Check out our visit to the Clayton mansion at The Frick Pittsburgh and discover the house’s many secret compartments.The post What’s in the basement of the Squirrel Hill Tunnel? appeared first on NEXTpittsburgh.