Mayor Rob Ford was photographed reading a document while driving on the Gardiner Expressway Tuesday morning, prompting questions about his behaviour behind the wheel for the third time in just over a year.

The photo was posted on Twitter. Ford unapologetically acknowledged its authenticity when asked about it at an unrelated news conference later in the morning.

“Yeah, probably,” he said flatly. “I’m busy.”

When a reporter followed up by asking whether he reads while driving, he said, “Yeah, probably. Trying to catch up on my work; you know, keep my eyes on the road, but I’m a busy man.”

When the reporter asked whether he doesn’t see a problem with reading on the Gardiner, he said again, “I’m busy.”

The news conference, held to announce a city trade mission to Chicago in September, was delayed from 11 a.m. to 11:30 a.m. because Ford was late. It is unclear what Ford was reading, but the text in the document has the large font Ford often uses for his prepared speeches.

Ford was unhappy to be taken off message at the news conference. “I don’t know what that has to do with the trade mission, but anyways,” he said to conclude his exchange with the reporter. “Ridiculous questions sometimes.” An aide then interjected to say Ford would take only one more question.

The photo showed Ford behind the wheel of his new Cadillac Escalade holding the document in his right hand. The person who posted it, Ryan Haughton, said it was taken around 10 a.m.

Haughton later deleted the photo and his subsequent tweets about it, and he did not respond to an interview request. He had directed the photo to radio host Dean Blundell, who frequently mocks Ford on 102.1 the Edge. “@ItsDeanBlundell look at the pork chop Ford reading and driving on the Gardner #leadingbyexample,” Haughton wrote.

Haughton’s tweet came to the media’s attention when it was retweeted by Adrienne Batra, Ford’s former press secretary and now a Toronto Sun editor.

This is the third time in just over a year that Ford has been accused of driving unsafely. His brother, Councillor Doug Ford, has publicly urged him to have an employee serve as his driver, as past mayors have, and he did so again at the news conference.

“Absolutely, 100 per cent,” Doug Ford said.

In July 2011, Ottilie Mason said she saw Rob Ford illegally using his cellphone while driving; after she and her daughter gave him a thumbs-down gesture, she said, he gave them the finger. Ford called the incident a “misunderstanding,” but he soon purchased a hands-free phone system.

In June, Ford had a verbal altercation with a streetcar driver after he drove past the closed back doors of the vehicle when the front doors were open to allow passengers to exit. A police spokesperson said this was not illegal but that it is safest to stop behind all doors.

Ford was long known for driving an old beige minivan with a “ROB FORD” vanity plate. He later changed the plate to “DON BOSCO,” the name of the high school whose football team he coaches.

In July, he became both less and more conspicuous on the roads: he switched to a standard plate, but he began driving the large luxury SUV his brothers bought him as a gift for his 43rd birthday.

Ford has spoken often of his penchant for returning residents’ phone calls while driving. It is not clear how fast he was travelling when he was photographed on Tuesday.