Some students, residents worry, will crave a rowdier college experience. Lisa Trader, 36, said she relished that her children, ages 8 and 6, could “just run” freely when they got off the tram. If the neighborhood dynamics changed, she said, perhaps the island’s more idyllic charms would disappear. “I don’t need to go back to college,” she said. “It would be a shame for it to turn into a party island.”

Ms. Torres said Roosevelt Island families need not worry. “This is Cornell,” she said. “One would assume they’ll be working.”