Plans for urban development along Montgomery County’s Interstate 270 corridor have angered parents and school officials threatened by overcrowded classrooms and possible redistricting.

A draft proposal by the county’s planning commission to develop new homes and businesses near the White Flint Metro station would bring more than 400 new elementary students, according to school district projections. Similar plans — with similar potential for controversy — are moving forward at other sites along the corridor, such as Germantown, Gaithersburg and Clarksburg.