A Lawrence, Mass., woman says she saved the lives of her twin daughters after she used herself as a "speed bump" to stop her car from rolling into traffic.

Mindy Tran, 22, says she had been living in a shelter with twin daughters Saleen and Sydney, and that they had recently moved into their new apartment just days before the incident.

"It felt like I was starting a new life," she told ABC News today from the hospital where she is recovering from a broken leg and dislocated shoulder and hip. "The girls had started at daycare and we just moved in. It seems like when things are going too well, something bad will happen."

Tran says she is lucky to be alive after she lay on the ground behind her Honda Accord to stop it from rolling into the street with her kids still inside. "I laid down horizontally, using my body as a speed bump to stop the car," she said.

(Photo Credit: Courtesy Mindy Tran)

Her 2-year-old daughters were buckled in the back seat when the car started rolling. A neighbor also came to help.

"My neighbor jumped in and he asked what I wanted them to do," she said. "I said make sure my daughter's got out of the car safely."

Her neighbor was able to get the girls out and they were uninjured, she added. "My daughters and I are all right and keeping our heads up," she said. "I'm lucky to be alive."

There was no damage to the car, Lawrence Fire Department Chief John Marsh said. "Firefighters responded to the apartment and they stabilized the car with wooden blocks and then used an airbag to lift the car off Tran," he said, adding that she was eventually airlifted to a Boston-area hospital.

"We've seen something like this before," he said. "It is an unfortunate accident and somehow her car wasn't in gear."

Tran says she cannot walk and will have surgery in the coming days, along with physical therapy. "I crushed my knee, injured my hips and dislocated a shoulder," she said.

Tran's twin girls will celebrate their birthday April 13. She says the medical facility at which she is staying has offered to let them have a party there so she can be with them.

"It's not going to be the same for them celebrating a birthday here at the hospital," she said, "but as a mother I want to see them."

Tran says she could be in the hospital for a few weeks.

"I don't consider myself a hero," she said. "I am just a mother."