On July 16, 1981, Chapin was driving in the left lane on the Long Island Expressway at about 65 mph on the way to perform at a free concert [note the speed], scheduled for later that evening at Eisenhower Park in East Meadow, New York. Near exit 40 in Jericho, he put on his emergency flashers, presumably because of either a mechanical or medical problem.
He then slowed to about 15 miles (24 km) per hour and veered into the center lane, nearly colliding with another car.
He swerved left, then to the right again, ending up directly in the path of a tractor-trailer truck. The truck could not brake in time and rammed the rear of Chapin's blue 1975 Volkswagen Rabbit, rupturing the fuel tank as it climbed up and over the back of the car, which burst into flames.
The driver of the truck and a passerby were able to get Chapin out of the burning car through a window after cutting the seat belts before the car was engulfed in flames. Chapin was taken by police helicopter to a hospital, where 10 doctors tried for 30 minutes to revive him.
Although Chapin was driving without a license – his driver's license having previously been revoked for a long string of traffic violations – his widow Sandy won a $12 million decision in a negligence lawsuit against Supermarkets General, the owners of the truck, based on what Chapin would have earned over the next 20 years. An earlier phase of the trial had found Chapin 40% negligent in the accident and Supermarkets General 60% negligent, so the award of $12 million for the financial loss to the family was automatically reduced to $7.2 million.
Dr. Minoru Araki, Nassau County's deputy chief medical examiner, said Chapin's aorta was lacerated by the tremendous impact and he died of massive hemorrhaging into his chest cavity. Araki said a report that Chapin may have suffered a heart attack at the wheel was erroneous. "He suffered a cardiac arrest as the result of his severe injuries, but the autopsy showed that his heart was in very good condition," Araki said
Chapin's daughter Jennifer said, "My dad didn't really sleep, and he ate badly and had a totally insane schedule."
