> They're only unique in trivial ways. Roads are made of the same material everywhere - they're different only in some strict geometric sense. That's about as

> They're only unique in trivial ways. Roads are made of the same material everywhere - they're different only in some strict geometric sense. That's about as accurate as saying that software projects are only unique in trivial ways because there's probably already a free library or plugin that can do whatever else you need. It's easy to assume your occupation is much harder than everyone else's but we rarely have deep knowledge of the challenges other people face day to day outside of our own line of work. As a simplified example, the design of a road, its pavement layers and its foundation is determined by factors like traffic loading characteristics, service requirements (peak capacity), speed limits and visibility, ground conditions, climate and more (see Caltrans' Highway Design Manual at http://www.dot.ca.gov/design/manuals/hdm.html http://www.dot.ca.gov/design/manuals/hdm.html), many of which rely on professionals in entirely other fields.