Civilians see a new road being built and may welcome it or complain about it. Rarely does the public at large understand all of the planning that goes into making a simple access road or a new highway. I have been through hour upon hour of a Civil 3D tutorial that teaches how software is used to plan even the smallest road projects. You can’t just drop down some pavement and connect your new road to an existing road or intersection. It needs to be planned. The old way took thousands of man hours looking at aerial views, estimating traffic flows, determining how much traffic is already on the surrounding roads, and the best place to intersect the new road with an existing road.
An example of planning is how we made an in and out road for a local shopping complex. You can drive around the back of an anchor store to take a shortcut to the exit road. That area is made for deliveries, but access is not restricted. People asked why they have to drive all the way to the other end of the complex to get to the exit road, when a cut through the grassy area in the middle would let them get on the road out. Well, the planning showed that trucks using such an access would be a risk to motorists because there would only be a stop sign there. Cars could get out, but trucks would be a hazard. So, we force everyone to go to the traffic light at the end to get out. I imagine people still grumble about it when driving back there, but it is to keep them safe.
The software we use to plan roads helps us see problems before the millions of dollars are spent to pour the concrete and lay the pavement. We even plan for things such as getting access to things under the roads such as pressurized sewer lines or water lines that may need repaired years from now. All of it is run through risk and cost analysis algorithms to keep people safe, save money and keep traffic flowing.