Every construction or infrastructure project begins with a grand vision. Let's say you've performed some consulting work for an upscale mall developer. His grand vision included thousands of happy shoppers scurrying into his newly completed mall to nosh at the food court and buy from their favorite glitzy stores. When they emerged laden with packages, they easily made their exit through a well-designed network of parking lots and mall perimeter roads. Happy shoppers? Absolutely. Happy mall merchants? Definitely.
Of course, the developer would have been left holding the Nordstrom's bag without your expert guidance. You advised him, and your soil tests confirmed, that building his megamall on top of a swamp was risky. He grudgingly laid out the funds for additional foundation work. You recommended an environmental impact statement because there had been a nearby toxic dump 40 years ago. You saved him a ton of headaches there, too. Finally, you fielded lots of pointed questions at a pre-construction public hearing. Without your civil engineering savvy, the guy would probably still be looking at a few acres of mud and swamp grass. He owes you big time.