(CBS) — A Milwaukee County bus driver is being called a hero, after she rescued a toddler found wandering alone in the cold last month, barefoot and dressed in only a onesie and a diaper.

Irena Ivic was driving her regular route on Dec. 22, when she spotted a child running down the street alone, in below-freezing temperatures. Video from security cameras on the bus show the toddler walking barefoot down a freeway overpass.

The Milwaukee County Transit System bus driver said she couldn’t believe her eyes. She quickly pulled over, and rushed into oncoming traffic to scoop up the child.

Ivic took the toddler back to her bus, where a passenger gave up her coat to keep the child warm.

The bus driver cradled the child, who fell asleep in her arms before police and firefighters arrived.

“Oh my God, I was so upset, and I couldn’t believe that somebody can left the child on street,” Ivic said.

Ivic said she wouldn’t hesitate to help if she were in the same situation again.

Investigators said the girl is less than a year old. Police said her mother left her outside, and might have been experiencing a mental health crisis. The girl was reunited with her father.

Ivic received a special citation on Thursday. MCTS officials said the girl was the ninth missing child bus drivers have reunited with their families in recent years.