While we're celebrating our country's birth this Fourth of July, remember this is one of the things that makes America so great.

Police in Hanson, Mass., teamed up with Army soldier Alan MacAllister to surprise his mother when they stopped her while driving. Officers told Darlene MacAllister to get out of her car, enabling her son to sneak up behind her for the delightful moment. One of the officers recorded the incident.

Not all traffic stops are negative! Welcome home PV2 Alan MacAllister! We were honored to assist in reuniting Allan and his Mom, Darlene today.

Posted by Hanson Police Department on Monday, June 29, 2015

Darlene said she was totally blindsided. "It definitely caught me off guard," she said. "I just hung up the phone with him saying he wasn't going to be home because his flight was canceled. The police officer had him call and tell me that."

Alan is an engineer based in Colorado. His prank may have gone off without a hitch, but he'd better be ready because his mother is planning to retaliate with her own joke. She said, "Oh, I've already got mine figured out."