A man embarking on a cross-country charity trip on a recumbent bicycle to raise money for children with cancer was killed Tuesday afternoon after being struck by a car on a Mississippi highway, authorities said.

James Dobson, of Lebanon, Maine, started his Positive Vibes Tour in New Hampshire on Oct. 1 for the Children’s Hospital at Dartmouth-Hitchcock. His goal was to ride 60 miles daily, to San Diego.

It was his 44th day on the road when a 2016 Dodge Challenger struck Dobson, who was riding his bicycle, while he was traveling west on the US 98, according to the Hattiesburg American.

Hunter Buckley, the driver of the vehicle, said he was unable to avoid hitting Dobson. The accident is under investigation.

Dobson, 32, was pronounced dead at the scene.

Friends of Dobson praised him for his character, telling the paper, “You couldn’t meet a nicer person.”

“James was infectious,” Doug Bower told the Hattiesburg American. “His personality was fabulous.”

Keith Loud, the hospital’s physician in chief, said in a statement that he was moved not only by Dobson’s dedication but the courage it took to ride across the country in an effort to give back.

“A self-proclaimed ‘small-town regular guy,’ James was a shining star, and we are honored to have had him shine his light in our direction,” Loud said. “We express our deepest condolences to his friends and family.”

Dobson made the trek to San Diego to raise money for the hospital once before, driving a minivan cross-country and having people sign it along the way, the paper reported.

James Richesin, another friend of Dobson, told the paper Dobson spent three months training to prepare for the cycling tour.

“He wanted to do something amazing,” Richesin said. “So he set his mind to it.”