Secretive Transportation Research Center provides rare look inside

EAST LIBERTY — Hidden among the hills and trees of East Liberty are 4,500 acres of gearhead nirvana. The Transportation Research Center is a place where fast cars can push their limits on a 7.5-mile track, right next to a rocky obstacle course that would challenge even the most rugged trucks. It all exists behind a security perimeter so the center can protect the secrets of its clients, which often include prototypes of new vehicles.