BLUE HILL, Neb. — When a school bus collided with a tractor-trailer here in 2012, motorist Philip Petr stopped and provided critical help to students on the bus.

Now, Petr has won a Carnegie Medal for his life-saving actions.

In the Sept. 5, 2012, incident, the school bus collided with the tractor-trailer, which was hauling hay bales, and the vehicles came to rest in a ditch. Fire broke out in the wreckage and began spreading.

Petr, a 46-year-old research technician, was approaching the scene and saw smoke. When he stopped, a boy who had escaped from the bus told him that others were still inside.

Petr found that the bus' service door was jammed shut and the rear emergency door was blocked, so he grabbed a tool from his truck and broke out a window on the side of the bus.

Another man who had stopped at the scene hoisted Petr so he could climb into the bus. He handed two of the remaining children through the window to the other man, and then he crawled over dislodged seats that were blocking the aisle to reach 18-year-old Dustin Tesdahl, who was badly injured.

As smoke filled the bus, Petr took Tesdahl to the front of the vehicle and handed him out to the other man. Two other students escaped through a broken window.

Tesdahl died from his injuries. Also killed in the crash were 10-year-old Caroline Thallman, bus driver Marla Wentworth and truck driver Travis Witte. Petr sustained a minor burn on his leg.

In December, the Carnegie Hero Fund Commission named Petr a recipient of the Carnegie Medal. The award is given to "those who risk their lives to an extraordinary degree while saving or attempting to save the lives of others," according to the commission.

A total of 77 people won the Carnegie Medal in 2013. Commission President Mark Laskow said that each of the awardees or their survivors will also receive a financial grant.

Since the Carnegie Hero Fund Commission was established in 1904 by industrialist-philanthropist Andrew Carnegie, more than $35.6 million has been given in one-time grants, scholarship aid, death benefits and continuing assistance.