Toyota revealed the settlement in a letter to a Santa Ana Superior Court judge, but the company gave no details about the terms and wants to keep them confidential, the Los Angeles Times said in a story posted on its website.
California Highway Patrol officer Mark Saylor had borrowed the Toyota-made Lexus ES from a dealer in August 2009.
He was killed along with his wife, her brother and the couple's 13-year-old daughter after their accelerator became trapped by a wrong-size floor mat on a freeway in La Mesa, near San Diego. Their car hit a sport utility vehicle and burst into flames.
"Toyota and the Saylor and Lastrella families reached an amicable agreement in mediation that fully resolves their product liability claims against Toyota," the automaker said in a statement Friday.
The Times said Toyota is expected to file motions with the judge disclosing the settlement on Monday.
An attorney for the plaintiffs, who included the parents of Saylor and the two other adult victims, declined comment when reached by the Times.
The case was considered the strongest of hundreds of lawsuits over claims stemming from sudden acceleration in several Toyota models, and brake glitches with the company's Prius hybrid.
On Tuesday the automaker moved to dismiss the federal lawsuits that have been consolidated under a judge in Santa Ana.
Information from: Los Angeles Times, http://www.latimes.com