Matthew Petke, 39 and Brenda Petke, 45, were killed in the crash on Sunday night.
The crash happened around 7:00 p.m. on Route 41 in front of the Taqueria Moroleon Mexican Restaurant in Kennett Township, near the Delaware-Pennsylvania state line.
Officers say the car had just pulled out of the parking lot on Gap Newport Pike when it was hit by the passing tractor trailer.
The tractor trailer then went off the roadway, puncturing its gas tanks.
The tractor trailer driver, 35-year-old John Deapen, was uninjured.
The circumstances of this crash remain under investigation.
Mark and Brenda Petke, from Wilmington, Delaware, were well-known activists and advocates for people like themselves, those with intellectual developmental disabilities.
"Both Matt and Brenda were leaders as self-advocates, volunteering for organizations," said Stephen Know of the ARC of Delaware. "They did many, many projects with us."
The couple held down full time jobs at Bank of America, pioneers in a program that now has 200 people with intellectual disabilities working for the bank.
"They were living the American dream, they wanted to be like the rest of us. They had a house, they lived together, they had friends over, they went to work every day," said Marybeth Limmina of the ARC of Delaware.
They were married 11 years ago and were establishing their growing independence in their own home. The minister who married them said the couple had becomes pillars of the church and they were working with the Sunday school.
"They were teacher's aides and they were loving and accepting and affirming. They would help bring out the best in the little people and the little people could feel very comfortable in their presence," said the Rev. David Lovelace of the Lower Brandywine Presbyterian Church.
"They were very faithful," the Rev. Lovelace added. "Whenever the church's doors were open, they were there."