Ryan Anthony Guillen, 21, and his sister, Kimberly Guillen, 18, sued the tire manufacturer last November after their mother and stepfather were killed when their Ford Explorer crashed May 30, 1999.
Nidia and Patricio Leal died when a Firestone tire unraveled, sending the vehicle skidding into a ditch near Brownsville, Texas.
"These are horrifying events for families to go through, that have to deal with the aftermath of these events, and my experience in handling cases like this is time does not erase grief," Robert J. Patterson, a lawyer for the siblings, told CBS Radio News.
Details of the settlement were not disclosed, under the terms of the agreement.
"I think they have made a business decision to address these issues," he said, speaking from Corpus Christi, Texas. "Clearly, it's hard to sell tires while people are deposing your executives."
Bridgestone/Firestone spokesman Daniel Adomitis denied it was purely a business decision.
"We consider it a tragedy any time someone is injured in an accident involving our products. Bridgestone/Firestone has reached an agreement in principle in this case, and we are committed to working with all the parties to finalize that agreement as quickly as possible," he told CBS Radio News.
"Firestone is doing jury studies, and if their studies are showing what ours are, they don't have a chance," Patterson told The Wall Street Journal.
The case was filed in state district court in Rio Grande City, Texas, and was set to begin trial on Nov. 13.
In August, Bridgestone/Firestone recalled 6.5 million ATX, ATX II and Wilderness AT tires. The tires are being investigated in 119 deaths and 500 injuries in the United States, and more than 50 deaths elsewhere.
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