Technophile Bruce S. Cridlebaugh has compiled this website of information on the bridges and tunnels of Allegheny County and Pittsburgh to satisfy his curiosity. The information featured here has been primarily gathered by visiting the various bridges and tunnels and making on-site measurements, sketches, photos and notes. Despite limitations due to the nature of some sites, such as "a given location, private property, high traffic, and so on," he has gathered information on almost 50 structures. Visitors can browse the collection by the structure's location, design, name, or use. Books, magazines, newspapers, maps, and Internet resources used to develop the website are listed in the Information Source section or in the Other Info section. The author also provides an overview of Bridge Basics and explains common terms used in Engineering, Masonry, Metal work, Bridge and Tunnel building, as well as Mapping.