Until there is more evidence to show the program works, he said, “my attitude is skeptical hope.”

Despite the lack of data, young adult courts are gaining traction. Last year, the federal National Institute of Justice tallied six such courts around the nation, in places as diverse as Idaho, Nebraska and New York.

The Center for Justice Innovation, a British charity, is about to start a pilot program of five young adult courts in England and Wales. Staff members visited the San Francisco and New York courts in February to learn more.

The San Francisco court “is the type of model we would want to see,” said Brent J. Cohen, a former senior policy adviser at the Department of Justice, now managing director of Public Service Consulting Group. “I think it’s probably the first model in the country that really takes into account the neuroscience and does robust training for its staff based on that.”

Shaquille is scheduled to graduate in the next few months. He plans to continue pursuing his ambition to become a licensed security guard — a dream that would evaporate with a felony record.

While he regrets impulsively punching the other driver, he said the court’s therapy classes had helped him with emotional restraint. “When things get overwhelming,” he said, “I can look at things before I react.”

A few months ago, after meeting with a case manager to fill out housing applications, Shaquille heard someone yell a racial epithet at him on a street corner. Shaquille felt the anger well up, but this time he kept walking.

“It ain’t even worth it,” he said.