Driving through a windowless tunnel for 20 minutes can get a bit monotonous, so a team of psychologists and engineers focused on retaining driver concentration. "The psychological reaction of a person in a tunnel is very important … it makes the difference between people accepting the facility or simply just avoiding it," says Youssef Hashash, a professor of Civil and Environmental Engineering at the University of Illinois, who has worked on 10 different tunnel projects. "Given the length of this tunnel, you need a carefully designed environment and lighting system." Some solutions used in the Laerdal tunnel include bright blue lights and subtle curves that keep drivers engaged. Most important, though, is the fact that the tunnel is divided into several different sections, breaking up the drive and creating the impression that commuters are traveling through a handful of smaller tunnels.
http://www.popularmechanics.com/technology/transportation/4343590.html -via Unique Daily