The cause was complications of injuries sustained in falls, his daughter, Mara O’Connell, said.

In 1965 Mr. O’Connell joined with Robert E. Keeton, another law professor, to write “Basic Protection for the Traffic Victim: A Blueprint for Reforming Automobile Insurance,” a book in which they proposed to do away with a system in which an collision victim had to sue another driver to collect damages, in most cases from the second driver’s insurer.

The authors proposed that the victim’s own insurance company would pay the damages instead, regardless of who was at fault. The other driver would recover damages from his own insurance company.

Except for cases of extreme loss, in which lawsuits would be permitted, suits to get greater sums would be prohibited, depriving personal-injury lawyers of a ready supply of clients.

As a result, the authors contended, everyone could be quickly compensated, and administrative costs, particularly legal ones, would be curbed. Logically, insurance payouts would drop, meaning car owners’ premiums could be reduced.

Mr. O’Connell and Mr. Keeton went beyond the usual academic analysis to travel the United States and elsewhere to lobby for their proposal; they even drafted legislation for some states. They also hired an actuary to calculate the savings no-fault insurance could generate.

Starting with Massachusetts, 16 states and several Canadian provinces adopted versions of no-fault insurance. Since the 1970s, four states have dropped the system, while others have weakened it by allowing suits to continue after specified amounts of damages have been paid.

Trial lawyers have maintained that no-fault’s projected cost savings have never materialized; the system’s proponents say it has been the lawyers’ own determined opposition that has prevented the savings from being realized.

“The trial lawyers have basically shot no-fault in the foot,” Mr. O’Connell said in an interview with Governing Magazine in 1997, “and now they complain that it limps.”

Jeffrey Thomas O’Connell, the son of a building contractor, was born on Sept. 29, 1928, in Worcester, Mass. He graduated from Dartmouth and Harvard Law School before serving in the Air Force in Korea. He was a trial lawyer with a Boston firm and taught personal injury, or torts, law at the University of Iowa.

“I quickly found that torts law is a disaster,” he said in an interview last year.

While teaching in Iowa, Mr. O’Connell wrote a letter to Mr. Keeton, a torts expert at Harvard Law School, saying the whole system urgently needed to be reformed. Mr. Keeton responded by asking him to come to Harvard to collaborate on a book about automobile tort law.

Mr. O’Connell characterized their work as “a practical, thought-out, detailed proposal that a legislature could simply take and revamp according to its local format.” In Massachusetts, they calculated that excessive overhead costs meant that $2.20 must be paid in premiums for every dollar that was paid out to an collision victim. They ended up testifying in virtually every state.

After his year at Harvard, Mr. O’Connell taught at the University of Illinois for 15 years before accepting a teaching post at the University of Virginia School of Law. In 1966, he joined with Arthur Myers to write “Safety Last: An Indictment of the Auto Industry.” The book, along with one by the consumer advocate Ralph Nader, “Unsafe at Any Speed”(1965), inspired debate in Congress.

Mr. O’Connell went on to write or help write 10 more books and 100 articles, several of which argued that the no-fault concept should be extended beyond automobile coverage. David Sanford, writing in The New York Times Book Review, said that Mr. O’Connell’s 1975 book, “Ending Insult to Injury,” was “brilliantly argued.”

Mr. O’Connell’s wife, the former Virginia Kearns, died in the mid-1990s. In addition to his daughter, Mara, he is survived by a son, Devin; a brother, Thomas; a sister, Jesslyn McNamara; and four grandchildren. He retired from the University of Virginia last year after 32 years at the law school. Mr. Keeton died in 2007 at 87 in Cambridge, Mass.

Last July, the New Hampshire legislature, overriding the veto of Gov. John H. Lynch, a Democrat, passed a bill to permit the quick settlement of malpractice claims out of court in the manner of no-fault insurance for cars. Mr. O’Connell had testified before a legislative committee on behalf of the bill.