Threlkeld was driving his 2008 Mini Cooper in Amagansett when he collided with a propane tanker, according to the East Hampton Police Department. He was pronounced dead at Southampton Hospital, not far from his home in East Hampton.
Threlkeld was a broadcast journalist for 36 years and spent 25 of them at CBS News as a correspondent, anchor and bureau chief. He left CBS for seven years in the 1980s to work for ABC News, where his "Status Report" features earned an Alfred I. duPont-Columbia University Award in 1984.
He returned to CBS in 1989 and was the network's Moscow correspondent from 1996 to 1998, an assignment that inspired his 2001 book, "Dispatches from the Former Evil Empire."
"Richard Threlkeld had the kind of name and kind of looks that could've made him a reporter in the movies, but unlike a reporter in the movies, he could write his own scripts," Lesley Stahl, his co-anchor on the CBS Morning News from 1977 to 1979, said in a statement Friday. "In fact, he was one of our best writers and reporters, someone CBS sent to troubled spots to cover the big stories of the day."
He was one of the first correspondents to report live from the front during the Gulf War and from Kuwait City after it was liberated. He was one of the last journalists evacuated from South Vietnam when it fell to Communist forces.
At home he reported on the Patty Hearst kidnapping, the assassination of Sen. Robert F. Kennedy and numerous presidential campaigns, from Richard Nixon to Bill Clinton.
Threlkeld was born Nov. 30, 1937 in Cedar Rapids, Iowa, and grew up in Barrington, Ill. He studied political science and history at Ripon College in Wisconsin and earned a master's degree in journalism from Northwestern University in 1961.
In 1966 he began his CBS career as an editor-producer in New York. He later was assigned to bureaus in Los Angeles and San Francisco.
"He was old school in the best sense," said CBS News correspondent Bob Simon, who covered the fall of Saigon with Threlkeld in 1975 . "He really didn't give a damn about being on camera. He didn't do many stand ups. He always figured there was more interesting footage than himself."
At "Sunday Morning," which debuted in 1979, Threlkeld was known for his prolific reporting, turning out the principal news story for nearly every broadcast in the show's early years. While other staffers slept while returning on long flights from overseas assignments, "Dick would be listening to a little recorder with all the audio from all the interviews and … transcribing it by hand. He was amazing," said Larry Doyle, who produced many of Threlkeld's stories.
For the last 28 years, Threlkeld was married to Betsy Aaron, a former correspondent for CBS, ABC, NBC and CNN, whom he met in 1977 when she was recovering from serious injuries sustained on assignment when a car careened into a Ku Klux Klan rally in Georgia.
After Threlkeld retired in 1998, he and Aaron moved to Tucson. According to Richard Leibner, his longtime agent, the couple moved full-time to the Hamptons a few years ago.
In addition to his wife, Threlkeld is survived by two daughters from his first marriage, Susan Paulukonisof Alameda, Calif., and Julia Threlkeld of Yonkers, N.Y.; a brother, Robert, of Port Townsend, Wash.; and two grandchildren.