GAINESVILLE, Fla. (AP) John Medlen remembers his son's final seconds like they were his first steps.
Eric Medlen inched his dragster to the starting line and waited for the signal. John, also his son's crew chief, made a couple of routine checks, looked in Eric's eyes, gave him a thumbs-up and pounded on the hood twice.
''Neither one of us realized he had a little less than three seconds to live,'' John said.
Ten years after Eric's fatal practice run at Gainesville Raceway, home to one of professional drag racing's premier events, John is still dealing with the demons that come from burying a child. Eric's death became a defining moment for NHRA, mostly because of the way John reacted to it and the safety changes he fought for.
''Eric would not want anybody here on this earth that's left to be burdened to the point where you can't live your life because of his death,'' he said. ''... I hear his spirit tell me all the time, `Keep going, Dad. Make these cars safe. Keep somebody else from having these kinds of issues.'''
Eric grew up around racing in Oakdale, California. His father placed his bassinet on a workbench in his garage, and he spent hours at drag strips. Even the school bus dropped him off in front of dad's race shop.
John steered his son toward other pursuits, and to an extent, that worked. Eric was a champion calf-roper in high school, then a mechanical engineering major in college.
But the track always beckoned. The man nicknamed ''Duff'' spent eight years working as a John Force Racing crewmember before the team gave him his big break as a driver in 2004.
''I tried to talk him out of it, but he wasn't going to have it,'' John said. ''If it had wheels, he was going to race it. Go karts, sprint cars, it didn't matter what it was.''
Eric won six times in 72 starts in the National Hot Rod Association and finished in the top five in points in each of his three years at the pro level. His death shocked the series, even if everyone associated with it knew the perils.
Drag racing has always been one of the most dangerous forms of motorsports, whether it's on backroads, city streets or professional strips. It became increasingly popular in the 1950s: Bigger engines, lighter cars, faster speeds - and increased risk.
Eric reached the top level, where nitromethane-powered dragsters race in side-by-side lanes and routinely top 300 mph in less than five seconds.
''You know what can happen. Everybody in the industry knows what can happen,'' John said. ''But we've never seen an injury like Eric's before.''
On March 19, 2007, a day after the NHRA's Gatornationals, Eric and his Force teammates stuck around to test at the historic track, a common move that allows teams to acquire valuable data while reducing travel costs.
As Eric, 33, pulled to the starting line, everything seemed normal. He released the trans brake, allowing his Funny Car to lunge down the track with the G-forces of a fighter jet. And in the blink of an eye, Eric endured a violent, mid-strip tire shake that snapped the chassis, caused his car to slide out of control and forced his head to whip side to side about 150 times. Goodyear later said something apparently punctured the tire at high speed, causing it to lose pressure and start jerking the entire car with more than 40,000 pounds of force.
John rushed to the crumpled car as it came to a stop against a concrete retaining wall, found Eric unconscious in the cockpit and started yelling at him to breathe. John could tell the wreck was bad. Then he saw a paramedic shine a flashlight into Eric's eyes, turn to a colleague with a look of desperation and try again.
''I'll never forget,'' John said. ''She threw that flashlight into the corner of the ambulance. You could tell this was serious.''
Eric's head swelled so much because of a traumatic brain injury that he was hardly recognizable in his hospital bed. Doctors worked around the clock trying to relieve pressure and improve blood flow to his brain.
Despite the aggressive treatment, Eric's body lost the ability to manage its salt and water levels.
After four days with no improvement, the decision was made to take Eric off life support.
He died immediately.
''People were mourning, people were hurt, people were dying inside,'' said team owner John Force, who stayed at the hospital with Eric's family. ''But they also were already thinking about moving ahead. They weren't going to let this happen again.''
Force's cars skipped the next race, and he canceled the reality TV show ''Driving Force,'' which focused on him and his three drag-racing daughters.
''We're not going back to making movies,'' Force said. ''We're going to learn how to build race cars.''
Eric's father led the charge, meeting with NHRA executives, competitors, industry experts and even military and NASA engineers. They studied metal energy, seatbelts, tires, padding.
''As long as I'm on this earth, I'm not going to have Eric give his life in vain,'' John said. ''We're the ones here that can make all that count for him and for his memory.''
Changes came quickly.
There were tighter tolerances for chromoly tubing used to build chassis. There were wider roll cages. There was thicker padding surrounding drivers' helmets. There were now seven seat belt attachment points, keeping drivers more tightly harnessed for added stability and support.
John Medlen, 66, works for Don Schumacher Racing now. Returning to Gainesville every year is the hardest part of his life. Sights, sounds, smells, all come rushing back like the crash was a day - not a decade - ago. He welcomes questions about Eric's triumphs and tragedy, mostly because they help remind him about the son he lost, the life they lived together and the reason he still works to make the series safer.
''It's very difficult, but you have to do it,'' John said. ''You've got to face your adversaries and deal with the demons. They're not going away.''
There have been a few NHRA deaths since Eric's - Scott Kalitta (2008), Neal Parker (2010) and Mark Niver (2010) - but none of those were caused by tire shake.
Six months after Eric's death, Force endured a similar tire shake during a race in Texas. The violent crash broke his left ankle, left wrist and several fingers and put a deep cut on his right knee. Force was airlifted to a nearby hospital, where he spent weeks before leaving in a wheelchair.
But the 16-time champion avoided any head trauma, which he attributed to the NHRA safety modifications put in place following Eric's accident.
Force responded by erecting life-size statues of Eric at his team facility in Indiana, and at his corporate headquarters in California. He created museums to house Eric's race cars.
He sees the impact they have on everyone, even his 5-year-old grandson.
''He pointed at the statue and goes, `What is that, Grandpa?'" Force recounted. ''And I said, `That's Eric Medlen. That's the guy that saved your Grandpa's life and I ain't never forgetting that.''
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