The knock on the door that changed Bill and Muriel Elliott's life forever came at 4 a.m. on Saturday, July 22, 2000.

It was the police - with some devastating news.

"They told us our son had been killed in a collision with a drunk driver," Bill, 64, tells PEOPLE. "My wife went down to answer the door because we were asleep and I heard her screaming."
John, 22, had graduated from the United States Naval Academy in Annapolis, Maryland, just two months earlier and was working there as an instructor. That night, he got off duty around 10 p.m. and headed north to his parents' home in Egg Harbor Township, New Jersey, to celebrate his mother's birthday. The accident happened in Woodstown, New Jersey.

The driver of the car that hit John died in the accident. He had been drinking for 10 hours straight - and had a blood alcohol level of 0.23 at the time of the crash. The man had been arrested and charged with driving while intoxicated two hours before the accident but was released to the custody of a friend, who let him drive again.

"We experienced every parent's worst nightmare," Bill says.

But the Elliotts were determined to make some good come from the tragedy. That same year, they founded the HERO Campaign, a nonprofit devoted to cracking down on drunk drivers.
"Out of that incredible heartbreak, we wanted to do everything we could to prevent this tragedy from happening to other families," says Bill, a retired hospital vice president.

The HERO Campaign promotes the use of designated drivers by registering volunteers to drive home those who have been drinking. It partners with law enforcement agencies, colleges, bars and taverns, restaurants, sports teams, state divisions of highway safety, the U.S. Naval Academy and community chapters across the country.

Rodney Brewer, commissioner of the Kentucky State Police, says he's seen a drop in fatality rates since partnering with the nonprofit in December 2012.

"I can't let the HERO Campaign have all of the credit, but I will tell you I think they are a major part of the equation," Brewer tells PEOPLE.

Bill and Muriel also worked with the New Jersey State Police to get John's Law passed in 2001. The legislation gives police there the authority to seize the vehicles of suspected drunk drivers and hold them for up to 12 hours.

Laura and Michael Horne, who lost their son Chad to a drunk driver in January 2010, say they are grateful to the Elliotts for all their advocacy efforts.

"When you lose a child in such a tragic way, it can either make you or break you as far as staying together as a family," Laura, 49, of Freehold, New Jersey, tells PEOPLE.

"I attribute the survival of my family to Bill and Muriel Elliott and this campaign because I don't know if we would have done without it, honestly," says Laura, who volunteers for the group.

Muriel says the HERO Campaign has helped keep memories of their son alive.

"John was always a positive person; he made you laugh," says the retired first-grade teacher, 64. "John would probably laugh at some of the funny things along the way, like being grand marshals at the NASCAR race - we know that he probably would have loved that."

Bill says drunk driving should be taken more seriously because it can devastate anyone out of the blue - just like it did to to them.

"I think the view is like lightning could strike and it will happen to somebody else but it won't happen to them," says Bill. "But lightning struck our family when they came knocking on our door that morning."