(CNN) A limousine carrying several couples to a birthday party failed to stop at an intersection in upstate New York and struck a parked vehicle, killing 20 people in the deadliest transportation accident in the United States in nearly a decade, according to authorities and a family member.

The 2001 Ford Excursion limo was traveling southwest on State Route 30 when it didn't stop at the intersection with State Route 30 A and collided with an SUV in a parking lot shortly before 2 p.m. Saturday in Schoharie, New York State Police First Deputy Superintendent Chris Fiore said.

All 18 people in the limo, including the driver, were killed, Fiore said Sunday. Two pedestrians near the unoccupied, parked 2015 Toyota Highlander also were killed, he said.

Valerie Abeling told CNN her niece, Erin Vertucci and Erin's husband Shane McGowan, who were married in June, were among the victims in the limo.

"My family is just going through a lot," Abeling said. "It's a horrible tragedy and there's no words to describe how we feel."

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