DALLAS (CBSDFW.COM) – In the kitchen, Angela Johnson has no fears.

On Tuesday, she grabbed some leftover bean soup and sausage from the fridge and started heating up dinner Tuesday night. Angela likes to cook with her father David on a regular basis. The Plano family tries to make sure she has a normal life.

Angela has a rare genetic syndrome that causes developmental delays.

“She is 31 functioning on five year old level,” says her father David Johnson. “She is basically defenseless, very vulnerable.”

Every day, a special needs Dallas Area Rapid Transit bus picks Angela up to take her to work in Dallas and drops her off back at home when she’s done.

But Johnson says on Monday, nobody was home and she was dropped off 10 minutes early.

He also says it’s not the first time that’s happened.

“When DART drops her off at the front door and just leaves her and I’m not here and she is here, a lot of bad things can happen,” Johnson said. “Nothing good can come out of that.”

DART has more than 11,000 special needs customers. Spokesman Morgan Lyons says Angela has taken around 500 trips and has been dropped off early 34 times.

“The operator may have made a mistake and I don’t know what happened yesterday (Monday), we counseled the operator about that particular incident,” said Lyons.

The Johnsons also say the bus driver sometimes leaves and doesn’t wait for Angela to walk through the front door.

On Tuesday, after her father called DART looking for answers, she was dropped off on time and the driver even watched her go into the house.

“This is a curb to curb service – not door to door service. What is required is that the customer be dropped off at the nearest safe point,” says Lyons.

The Johnsons pay $5 a day for the ride and say they’ve heard enough excuses for almost two years now.

“DART has a moral, ethical and probably legal obligation to ensure the welfare to a reasonable extent for the riders on their system and I don’t think they are doing it,” says Johnson.

The family is now looking into other options for their daughter.

They also want to meet with DART officials to see if anything else can be done so this doesn’t happen to anyone else’s child.