CHARLOTTE, N.C. -- Jason Leffler would have had a better chance of surviving his fatal crash in a winged sprint car in New Jersey if he'd had a full containment headrest similar to what is used in NASCAR, multiple safety experts told ESPN.com.
Leffler, 37, was killed in the June 12 race at Bridgeport Speedway when his 410 sprint car suddenly veered into the wall and then rolled multiple times.
Racing safety pioneer Bill Simpson and Randy LaJoie, a two-time Nationwide Series champion who now designs and builds race car seats, have studied the wreck. They agree that a 180-degree surround headrest might have saved Leffler's life at the 0.625-mile dirt track.
Medical examiner Dr. Fredric Hellman, who performed the autopsy, said the death resulted from a blunt-force neck injury caused by a head-whip-type motion.
New Jersey State Police have not released results of their investigation, although Simpson and others who have looked into the wreck have been told by those at the track that a failed part on the front end likely caused the car to angle into the wall at a high speed.
LaJoie, who once served on the New Jersey safety board, has been in contact with investigators regarding the accident. Simpson has talked to mechanics and other eyewitnesses who were at the track.
Both were told that Leffler, who was wearing a head and neck restraint designed to protect on frontal impacts, did not have a headrest sufficient enough to keep his head in line with the rest of his body on a lateral impact.
"My findings showed everything with the head and neck restraint is fine when you have a forward impact as long as it doesn't go past 30 degrees, from one side to the other," Simpson said. "There is no lateral protection with the head and neck restraint. Nothing.
"Your head can flop from side to side. There is nothing to stop it from doing that. That car that Leffler was driving, it did not have a 180-degree head surround like a [Sprint] Cup car has. When he crashed and landed on his side and stopped, his head kept going."
LaJoie agreed. "He wasn't contained," he said. "That's why we haven't killed anyone in NASCAR, because we learned not to let the body and head move. Your head, chest and pelvis need to stay in line as close as possible."
The HANS (Head and Neck Support) was mandated for use in NASCAR in 2002, the year after Dale Earnhardt died of a basilar skull fracture in a crash on the last lap of the Daytona 500. Teams eventually went to seats that are basically molded around the driver's body and head to keep anything from moving on impact.
There has not been a death on the Sprint Cup, Nationwide or Truck Series level since Earnhardt.
Simpson said the head and neck restraint will prevent movement of the head only 30 degrees to the left and right of a driver looking straight ahead. The system Leffler reportedly wore came from Simpson Safety Equipment out of Braunfels, Texas.
Simpson said he was not part of that design, but he has studied it.
"There's nothing wrong with that system," he said. "It's good. But they don't protect you after 30 degrees. You have to have some kind of a head support. Period."
Sprint Cup driver Dave Blaney, who was at Bridgeport, said there was no full headrest based on pictures of the car he saw before and after the wreck.
"That would make that type of wreck extremely dangerous," Blaney said of not having one.
Tom Buch, the owner of the 410 sprint car Leffler was driving, could not be reached for comment.
LaJoie said Leffler's seat had a lightweight piece of aluminum that he calls a head flapper that was not "adequate" to keep the head in place on a side impact.
"It's been in the market for 25 years," he said. "That's definitely not adequate head support for an impact like he took."
Simpson, 73, has worked in motorsports safety for more than 50 years. He now is teamed with NASCAR/IndyCar owner Chip Ganassi in designing safer football helmets for the NFL, colleges and youth leagues.
Leffler's death prompted him to get involved with Kenny Koldsbaek of Kenny's Components in Mooresville, N.C., in designing a full containment headrest for sprint car, midget and late-model teams.
"When this whole thing went down with [Leffler] we started digging to find out what the hell happened," said Simpson, who had known Leffler for 31 years and was on his way to see the driver when he learned of the death. "I told Kenny this what I think we should do. He agreed."
Koldsbaek agreed with the assessments of Simpson and LaJoie on the headrest.
"It looks like if he had a full containment seat with a full headrest things might be different now," he said.
They all hope Leffler's death prompts local short-track drivers to look into raising safety standards the way NASCAR did after Earnhardt's death. A full headrest and seat is one of the areas they all agree needs addressing.
LaJoie estimates 30 to 50 percent of drivers in cars such as the one in which Leffler was killed and late-model stock cars don't use them. Those who do, such as three-time Sprint Cup champion Tony Stewart, who spends almost as much time in sprint cars as regulars, feel safe.
"The systems in those cars can be greatly improved," LaJoie said. "On the short-track level, with better belt systems, seat mount systems and neck systems, I bet over 95 percent of the crashes are survivable."