LOS ANGELES (CBSLA.com) — We’ve all seen distracted drivers.

When a local teen saw one recently, he got out his cellphone and started recording. And then he called CBS2’s Investigative Reporter David Goldstein.

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Hrand Kalestians, 17, was riding in his mother’s vehicle on the 5 Freeway in Glendale when he noticed that a bus driver was not fully paying attention to the roadway.

Kalestians proceeded to use his cell phone to videotape the bus driver’s distracted actions.

In the video, the driver is seen holding a cell phone in one hand and the steering wheel in the other, all while traveling around 60 miles per hour. At one point, the bus driver appears to laugh while he watches something on the illuminated screen of his phone.

“I thought it was just like a quick check, maybe [a] quick check of his next stop but he was on it for like the whole time driving and he was swerving out of his lane,” Kalestians said.

The driver had the phone in front of his face for at least 40 seconds before the bus pulled ahead of Hrand’s car.

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He then showed the video to bus safety expert Robert Berkstrasser.

How dangerous is it that the driver is distracted?

“Extremely dangerous,” Berkstrasser says.  “If he comes contact with a vehicle that’s a quarter of its weight, a motorcycle, a small car, he is going to do, if not a fatality, there’s going to be some serious, serious injury.”

And that driver wasn’t alone.

Goldstein went on the 101 Freeway near Universal City and found another driver on a sightseeing bus. He is shown looking down at least 14 times at what appears to be a phone in the span of about 28 seconds.

He caught up with that driver at Universal Studios. The driver insisted he was only checking on the traffic.

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“That is no excuse for a professional operator,” Berkstrasser said. “If they’re in a situation where they need to re-calculate, or get their bearings or figure things they need to pull the bus over and find out where they’re going.”