A tunnel carries a roadway through a mountain or under a river instead of around or over those obstacles. Tunnels are very expensive to construct and maintain due to drilling, ventilation and maintenance requirements. Generally, most tunnels are located in mountainous or hilly regions, and examples include the Fort Pitt Tunnel (Interstate 279) in Pittsburgh and the Waldo [Robin Williams] Tunnel (U.S. 101) north of San Francisco.
Leave A Comment