It's one of the signature scenes featuring one of the signature lines of what may become one of the signature movies about Pittsburgh. Her arms outstretched like wings, Emma Watson stands up in the back of a fast-moving pickup truck in the Fort Pitt Tunnel -- David Bowie blaring as the yellowed subway tile of the tunnel walls pops into the nighttime Pittsburgh skyline.
Ms. Watson, star of "The Perks of Being a Wallflower," has repeatedly called shooting the scene "one of the best moments of my life." Stephen Chbosky, writer and director of the movie, is hoping that Pittsburgh teenagers won't try to make it one of the best moments of theirs.
"Please God stay in the car!" he wrote in the liner notes to the movie soundtrack.
The scene also is repeated later in the movie, with Logan Lerman's character, Charlie, taking his turn to brave standing in the speeding truck. The tunnel scenes are major parts of the 1999 novel, "The Perks of Being a Wallflower," also written by the Upper St. Clair native Mr. Chbosky.
Lest there be any confusion, teenagers of Pittsburgh, standing in the back of a pickup truck while driving through the Fort Pitt Tunnel is not a good idea.
For one, it's illegal.
"They can't even be back there, in an open bed truck like that," said State Trooper Robin Mungo. "We hope that people will use common sense and realize that it is against the law."
Such an act also violates seatbelt laws for those under 18 and probably would result in a citation for the driver for endangering another person. The Fort Pitt tunnel is monitored by cameras at all times, she said.
Not to mention, it's dangerous.
It doesn't take a physics professor to figure out that standing up in the open truck bed of a moving vehicle, without holding on, could result in some unintended consequences -- like flying out of said motor vehicle in the event of the slightest bump or swerve.
Or in the event that it does: "Even if the truck swerves a little left or right, then you will fall," said Kunal Ghosh, a Carnegie Mellon University physics professor.
In the past, police have dealt with "car surfing" teenagers or those performing motorcycle stunts, Trooper Mungo said.
"We try to downplay those type of things so people don't do it," she said. "We don't want to glorify it."
In 1993, two teenagers were killed -- one in Venango County -- after copying a scene in the high school football movie "The Program," in which team members lie down in the middle of a road to prove their toughness. The movie was then re-released with that scene removed.
Mr. Chbosky thought about the possibility of teenagers trying the stunt themselves, but he hopes that discussion of the safety precautions on the Internet and DVD extras will convince them otherwise.
"We took every precaution that you could possibly take -- we had so many safety cables on Emma [Watson] and Logan [Lerman]," he said. "People can understand that it's not as easy as it looks in the movie."
Filming the scene required shutting down the tunnel for two overnight stretches in March. The truck in the movie was going 50 to 60 miles per hour, and Ms. Watson insisted on doing the stunt herself.
The scene, as written in the book and the movie, "is the ultimate symbol of a transition," said Mr. Chbosky. "The tunnel scene is a symbolic rebirth, whether people look at it as a spiritual rebirth or a coming of age."
And for Ms. Watson, it was exactly that. "The Perks of a Wallflower" is her first major role since playing Hermione since the age of 9 in the "Harry Potter" series.
"I have never seen a young person happier in my life than Emma inside that tunnel," Mr. Chbosky said. "Emma has grown up inside the eye of a hurricane, and this was her chance to let go and be a kid."
Mr. Chbosky has never heard of anyone actually standing up in the tunnel -- it was a scene born of his imagination after driving through the tunnel so often as a kid. He laughed as he remembered the preliminary discussions about filming it.
"People were asking about CGI to do the tunnel, budgeting something like $200,000 for digital effects," he said. "They hadn't ever been to Pittsburgh. It's just the Fort Pitt Tunnel -- you don't need visual effects. It's one of the most beautiful things."
In the book and movie, it is just after Ms. Watson's character, Sam, stands in the back of the truck and the Downtown skyline becomes visible that Charlie, the protagonist, says one of its most enduring lines: "And in that moment, I swear we were infinite."
Anya Sostek: firstname.lastname@example.org or 412-263-1308. First Published September 28, 2012 4:00 AM