Missouri state highway workers mounted a long range acoustic device on the back of a truck during tests last fall. The sonic device produces a loud noise to warn motorists away from work crews.
Missouri state highway workers mounted a long range acoustic device on the back of a truck during tests last fall. The sonic device produces a loud noise to warn motorists away from work crews. Photo courtesy of the University of Missouri
Missouri state highway workers mounted a long range acoustic device on the back of a truck during tests last fall. The sonic device produces a loud noise to warn motorists away from work crews. Photo courtesy of the University of Missouri