At its completion in the early 1950s, Levittown included 19,600 homes. The new development was now a major suburban community that included 82,000 husbands and wives and their children. In a second wave of development and construction in 1951, the Levitt family created an additional Levittown community of 19,000 homes in Bucks County, Pennsylvania, near Philadelphia.

The suburban sprawl had begun. Families would fill them quickly. The growing popularity
and availability of automobiles also encouraged the flight to get out of big cities. The
National Highway Program of 1956 built highways and interstate roads connecting
rural areas to metropolitan areas, contributing to a flurry of even more suburban development.

What is the meaning of “development” in the context of Line 1?