What to Know One of the latest trends in custom car modifications, called “straight piping,” goes way beyond style; some say it could spark panic

The tweak involves removing portions of a car’s exhaust system to produce loud pops and flashes that fire like gunshots out of the tailpipe

A John Jay associate prof says the pops could fool ShotSpotter, a network of acoustic sensors used by police departments to detect gunfire

Tinted windows and hydraulic lowriders are so … 1990s.

One of the latest trends in custom car modifications goes way beyond style —and some say it could cause a dangerous panic among pedestrians.

The modification usually involves removing portions of a car’s exhaust system and “tuning” the computer that regulates a car’s fuel combustion to produce loud pops and flashes that fire like gunshots out of the vehicle’s tailpipe. On social media sites like Instagram, the I-Team found dozens of videos demonstrating straight pipe exhaust systems that have been altered using techniques called “straight piping” and “two-step” modifications.

Pedestrians said they could imagine a dangerous mass panic if one of the customized cars rolled past a crowded street.

“I’d freak out,” said Linda Marullo, a New Yorker walking through Times Square.

Teresa Leung, a Canadian visiting New York, watched the Instagram videos in disbelief.

“You want one word from me? Insane!” she said.

Sgt. Jessica McRorie, a spokesperson for the NYPD, said accessorized mufflers are illegal for multiple reasons, including their production of unreasonable noise and the dangerous open flames they can spark.

“The noise they produce will cause alarm to the public and can possibly have dangerous, unintended consequences because they sound like gunshots,” McRorie said.

But the risks ofof meddling with a car’s exhaust system may go beyond the potential of inciting a panic.

Eric Piza, an associate professor at John Jay College of Criminal Justice, said the loud pops coming from vehicle tailpipes have the potential to fool ShotSpotter, a network of acoustic sensors used by police departments to detect gunfire.

“That exhaust isn’t just a random loud noise in the environment,” Piza said. “I mean, it is truly mimicking the sound of gunshots.”

Piza, who researches the effectiveness of gunshot detection systems, said manufacturers of the technology have made strides to eliminate false positives, but studies show things like fireworks, backfiring automobiles, and even low flying helicopters have the potential to foil the acoustic sensors.

"The sound of gunfire, that’s one of the highest priority incidents you can have so police officers are always going to be dispatched immediately," he said. "If it turns out that a lot of these incidents aren’t really gunfire events -- if they’re caused by loud exhaust or low flying helicopters or whatever else can be a loud noise in an urban environment - then that’s certainly a problem."

The I-Team reached out the manufacturers of ShotSpotter. The company had not responded to our inquiry by the deadline for this article.

According to the New York Vehicle and Traffic law, it is unlawful to modify a muffler or exhaust system in a manner that would amplify or increase a vehicle’s noise level. The New York State DMV has yet to respond to an I-Team inquiry about straight pipe exhaust modifications.

Lisa Koumjian, a spokesperson for the New York State DMV, said motorists and car dealers caught driving or selling vehicles with altered exhaust systems could face a $150 fine and up to a month in jail.

“Modifying an exhaust pipe to sound like gunfire is not only illegal, it also poses an unnecessary risk to pedestrians, passersby and everyone on the roadway,” Koumjian said. “The DMV strongly encourages vehicle owners from making this kind of modification to their car.”