Me too! I have worked with both of the aforementioned companies, both back in the 90s when they were known as “Navigation Technologies” and “Etak”, respectively. One of my roles in my career in this industry was, in fact, driving around and collecting data. At first, we used paper printouts, and as a pair (one driving, and the other mapping), we would drive every street in an assigned area, and capture this field data directly on the maps, which would then be delivered to our digital mapping department, where they would digitize our scribbles.
The base digital maps were usually standard data from the government acquired very cheaply, but then we would add value by updating with aerial photo data (for positioning), and then the field collected map data that could not be captured via aerial photo (such as turn restrictions, points of interest, traffic barriers, addresses in some cases, best routes, etc).
Back in the day I worked with the prototype GPS data collection units, where we would leave a breadcrumb trail of dots for repositioning and adding geometry (instead of the more expensive and less reliable aerial photos). This is the kind of thing you may see on the Google cars these days that both take photos and assure GPS accuracy.
As far as the routing, each segment of road had attributes such as address ranges, and a network code - the higher the code, the faster it was supposed to be - so you would have something like 1=interstate hwy, 2=US hwy/expressway, 3= arterial, 4=collector, 5= neighborhood street, etc. The programmer wrote code to use these network designators. I am sure it is much different now. And, as suranyi states…
It was a cool, fun, entrepreneurial environment where we felt like we were doing something really different and cool and new.