Even in its current gentrified state, New York can be a dangerous place. But for years, its law enforcers have been educated at a deteriorating converted high school and a former shoe warehouse near the edge of Manhattan.

Fortunately, the City University of New York’s John Jay College of Criminal Justice owns an entire square block, west of Tenth Avenue between 58th and 59th streets, so when the time came to reconceive the school’s physical layout, it had the luxury of a space most colleges in the city can only dream of. Foundation and excavation work has now begun on the school’s $352 million, 600,000-square-foot expansion, which is expected to be completed by 2010.

Since the terrorist attacks of September 11, 2001, the school, which has been churning out investigators and law enforcement officers for 40 years, has seen a dramatic jump in enrollment, one that has shown no signs of abating. In 2003, after 15 years of bureaucratic tieups, the state Legislature finally approved the John Jay expansion project.

“The challenge is to create a true identity and sense of place for the students going to school there,” an architect at Skidmore, Owings & Merrill and a design partner for the project, Mustafa Abadan, said. “The facilities have not been up to the standards of a really good university. It was a unique opportunity because we had a fairly large site, by New York standards, and we could give the students a sense of community with the open campus commons, and in terms of the way we organized the buildings.”

The commons area will be created by setting a new 240-foot glass structure against the existing Haaren Hall. A Turkish immigrant who also worked on the Time Warner Center and the Memorial Sloan Kettering Cancer Center, as well as designing the mosque at the Islamic Cultural Center on 97th Street, Mr. Abadan said he wanted the glass building to symbolize the openness of law enforcement.

“Criminal justice is not something that should be hidden away. Glass makes the relationship to inside and outside clearer. It relates to our ideals of transparency and justice, the way justice is applied to everyone equally and openly,” he said.

Within the building, Mr. Abadan said, the design should mimic the dynamism of the rest of the city. His building features a series of open stairways and escalators that follow the site’s natural rise from Eleventh Avenue. The cascade replicates a miniature Manhattan, with the “travelers” passing through different building functions and academic departments rather than the squares — Madison, Herald, and Times, among others — that bisect Broadway and function as independent nodes within the city.

“It was the kind of thing that could embed a lot of ideas that go beyond just the functional usefulness that happens in purposeful buildings,” he said. “Not every building offers the kind of opportunity to embed architecture with more meaning than just being a kind of enclosure.”

The area around the college is undergoing a dizzying reconstruction — too much, really, for the designers of the John Jay expansion to attempt to situate the project within the context of the neighborhood. The architects instead sought to create a contrast with some of the older buildings in the area, including McKim, Mead & White’s Consolidated Edison power plant, whose main building has a late-1980s addition by Rafael Vinoly.

“I think it is important for everything to work together in a cohesive way, but that doesn’t mean it all has to look alike,” Mr. Abadan said. “It creates a notion that change is about to happen. Anything will be far better than what will be left behind.”

College officials say the expansion is necessary to accommodate the ongoing influx of new students. John Jay is currently shedding its associate’s degree program to become a fully accredited fouryear liberal arts college in the CUNY system.

“The new design will be transformative to our community,” the chief operating officer of the college and senior vice president, Robert Pignatello, said. “The space is badly needed because our enrollment is growing and interest in our school is higher than it’s ever been. We will soon have an incredibly distinctive vertical urban campus.”