What U.S. state was the first to adopt a no-fault auto insurance system?

Massachusetts was the first U.S. state to adopt a no-fault auto insurance system.

The state adopted its plan in 1970, after Massachusetts legislator Michael Dukakis introduced a modified version of the Keeton–O’Connell proposal in 1967. Governor Francis Sargent signed the legislation on August 13, 1970, and it took effect on January 1, 1971. The initial system provided first-party benefits for medical expenses and lost wages, reducing the need to establish fault before receiving certain payments.

No-fault insurance changes the traditional tort model. A driver generally turns first to their own insurer for covered injury benefits, regardless of who caused the crash. Depending on the state, injured people may still sue for serious injuries or damages above a threshold, so “no-fault” does not always mean lawsuits are completely impossible.

Massachusetts is sometimes confused with Michigan, Florida, or New York because each has had prominent no-fault rules. Puerto Rico adopted a no-fault plan in 1969, but it is a U.S. territory, not a state.