The kids couldn’t be stopped.

Bubble wrap laid out on the floor burst in loud pops under the tires of kids zooming by in motorized cars outfitted with harnesses and joysticks in a downtown office of Chicago’s Northwestern University.

While a 2-year-old girl waved to her family from her hot pink car, students from Northwestern cheered her on as she navigated the obstacle course’s twists and turns.

The cars had been modified for a handful of kids who have difficulties standing or walking independently, to give them a chance to be mobile and independent.

The cars’ creators are Feinberg School of Medicine and McCormick School of Engineering students, collaborating on a project for the course Clinical Management of the Complex Patient. The physical therapy and engineering students tested car speeds, took measurements and mapped out necessary modifications.

The motorized cars will be donated to the kids as part of the pediatrics series, said Jennifer Kahn, a physical therapist and the course director.

“We can teach them everything on paper, everything on a PowerPoint, but to really have that interaction with the kids gives them a whole new skill set,” Kahn said.

Spencer Oswald whizzed around the room strewn with pool noodles and tape measures in a shiny black car, using his chest to lean against a large button affixed to the steering wheel.

“That’s awesome,” said his father, Ryan Oswald, who watched his son try out the car for the first time. “It’s been tough to have things that match what he can do,” he said, noting that Spencer cannot walk or crawl. “It’ll be a great way to match where he’s at cognitively and physically.”

Jessica Trenkle, Spencer’s early intervention physical therapist, recommended Spencer for the car project.

A year ago, Spencer couldn’t sit up on his own. It was a challenge Northwestern students tried to tackle in a previous research project, when they created an adaptive 3D-printed seat that helped him do just that.

Renee Hensiek, a second-year doctorate physical therapy student, worked with Spencer then and also participated in the “Go Baby Go” project. “Now to see him, he sits and he’s ready for a car,” Hensiek said. “It’s cool to see all the different aspects of therapy come together.”

For some families, the project fulfills a financial need as well as a medical one.

At 6 months old, Stevie Browning was diagnosed with type 1 spinal muscular atrophy — the most severe — and was predicted to live between eight months and two years, said his mother, Samantha Angell.

Now, 2, Stevie can’t walk and needs support sitting up. Angell said she hopes to get him a wheelchair he can control himself. But their Medicaid health insurance denied their request for a motorized wheelchair, saying that Stevie didn’t understand the concept of cause and effect well enough to operate one.

Angell hopes the modified car will be a way to prove that Stevie is more than ready.

She watched as Stevie tentatively closed his fist around the red ball of the joystick and pushed. His eyebrows raised when the car, outfitted with a neck brace, harness and cup holder, moved on his command, jolting forward.

Bill Angell, Stevie’s grandfather, said seeing Stevie and the other kids test out their cars brought tears to his eyes. Rather than just watching others play, now they’ll be able to join in, he said.

“The inclusiveness is so important for these kids,” Bill Angell said. “It gives him freedom.”