When one of their daughters told them in the late 1970s that she was moving to the United States, Ana Julia Martínez and Jacobo Nuñez did not stand in her way. They were poor, illiterate farmers with a big family living on a ranch in the Dominican Republic. It was the only life they knew; they had different aspirations for their children.


“They were looking for something more” than could be found in the Dominican Republic, recalled Ignacio Nuñez, the couple’s oldest son, who added: “They agreed with her decision.”


The daughter, 21 at the time, moved to New York in 1979 and found a job in a garment factory in SoHo. Over the ensuing decades, 6 of her 11 siblings would follow her to New York — all finding work and, to varying degrees, realizing their parents’ long-held dreams for them. They would raise children, send some of them to private school, become homeowners and see the first of their family enter college.


But that smooth arc of family history was suddenly ruptured on Sunday when an S.U.V. carrying Ana Julia Martínez, 81, and Jacobo Nuñez, 85, as well as two of their daughters and three of their grandchildren, struck a median barrier on the Bronx River Parkway and plunged off an overpass, killing everyone in it.


On Monday, as the authorities continued to investigate the accident, scores of relatives and friends gathered at one of the family’s homes, a two-story, clapboard-sided house in the Bronx, to grieve the deaths and remember the victims. Their recollections described a narrative of hope and hard work, spanning four generations and bridging two countries.


“I always tell my mother, we could make a movie out of our family story,” said Nino Torres, 24, a grandson of Ms. Martínez and Mr. Nuñez and an architecture student at the State University at Albany. The story, he said, was about “how you could come from nothing to having something successful, having the American dream.”


On Monday, the authorities said they still did not know what caused the driver, Maria Nuñez Gonzalez, 45, to strike the median barrier. Paul J. Browne, a spokesman for the New York Police Department, said investigators estimated the speed of the vehicle, a Honda Pilot, at 68.5 miles an hour at the time of the crash, exceeding the 50 m.p.h. speed limit. He said there was no evidence that a tire blew out before the impact with the median, as some witnesses had reported.


Investigators said that after striking the median, the front left tire of the Honda was knocked off its rim. The vehicle then careened across other lanes of traffic before the right front tire hit a two-foot curb, launching the S.U.V. into the air, over a four-foot rail, and into a nonpublic area of the Bronx Zoo, 60 feet below.


In addition to Ms. Nuñez Gonzalez and her parents, the other victims included Maria Nuñez Rosario, 39; her daughters Naily Rosario, 7, and Marlyn Rosario, 3; and Jazlyn Gonzalez, 10, a daughter of Ms. Nuñez Gonzalez. The police provided different spellings of some of the victims’ names on Sunday.


The family plans to hold a wake for the seven victims on Thursday afternoon in the Parkchester section of the Bronx.


The victims’ roots wind back to a simple farm in Dajabón Province in the northwest of the Dominican Republic. The elder Mr. Nuñez had inherited the farm from his father and grew a range of fruits and vegetables, including avocado, mango, yuca and plantains, which he sold in local markets. They also kept livestock and other farm animals, relatives said.


“He could barely write his name,” Ignacio Nuñez recalled.


The couple eventually had 12 children, and the senior Mr. Nuñez had another seven with a second woman, his son said. In the decades after the first Nuñez sister migrated to the United States, five other sisters — including two of the crash victims — and a brother would follow.