New York City Transit officials say they have launched an investigation after a passenger photographed a bus driver typing on his cell phone as he steered through traffic.

The photo was published in the Staten Island Advance newspaper.

The paper says the picture was taken by a woman sitting in the first row of an express bus that travels between Manhattan and Staten Island.

She described the trip as “frightening.”

Transit Authority spokesman Charles Seaton says bus drivers are prohibited from using cell phones behind the wheel.