The City of Toronto’s transportation manager says it’s “possible” that a chunk of concrete fell from the Gardiner Expressway and smashed a woman’s windshield earlier this week.

However, Stephen Buckley says he has not been able to confirm what happened because crews have not located the chunk that allegedly fell.

City crews were sent to Lake Shore Boulevard and Spadina Avenue overnight to ensure the area beneath the highway is safe for the residents who drive, bike and walk beneath it.

That’s where Huma Saddiqi says she was waiting to make a left-hand turn when a piece measuring approximately 30 centimetres hit her passenger side windshield Tuesday afternoon.

"I'm so scared; I closed my eyes," she said on Wednesday. "I don't know if someone hit me or what happened at that moment."

Her son, Ali Saddiqi, whose vehicle was ahead of his mother's on Tuesday afternoon, said he heard a "loud bang" and thought two vehicles had collided.

"I look back in my rear-view mirror and I saw the van had the entire windshield smashed in and I saw a couple of pedestrians running over to my mom's car," he said.

Huma was not injured but Ali says she could have been. "What if it was a kid in a stroller?” he added.

After reports of falling concrete in 2013, the city budgeted $662.7 million over 13 years to rehabilitate the 18-kilometre expressway.

Buckley explained Friday that the city’s rehabilitation efforts include a “chipping program,” which removes hundreds of pounds of concrete at a time.

“We basically use hammers to sound out areas that could potentially sound like they’re not quite stable,” he explained.

Buckley says the program appears to be working, because the city has had only two reports so far this year of falling concrete. In 2014, there were 14 reports, four of which were “verified.”

Mayor John Tory said Friday that one piece of falling concrete is “one too many.”

Earlier in the week, Coun. Jaye Robinson, who chairs the city's Public Works and Infrastructure committee, expressed her concern.

"It's something clearly something the city should have dealt with many years ago,” she said.

Last year, city staff recommended tearing down a 2.4-kilometre portion of the Gardiner Expressway and replacing it with an eight-lane boulevard.

With reports from CTV Toronto's Natalie Johnson and Janice Golding