Most major historical cities are located near water of some kind (either a seaport or on a navigable river), so I find it hard to believe that roads were the driving force in determining where cities ended up.
But often it was rather some way of crossing the water that was that driving force. Oxford and Cambridge come to mind, or in Germany: Frankfurt (furt = ford), Erfurt, Saarbrücken (brücke = bridge).
If it was just about crossing water, you should also have random large cities in the middle of nowhere, but if you start looking at all the major cities of the world on a map, they’re almost all on a coast or a major river.
I thought that settling on a river is more for ease of access to a water supply than access to water as a mean of transportation. I may (surely) be wrong too.
