Bug or WAD?: Eliminating all roads prevent creation of new.

[Maelstrom Vortex]

All roads must begin with an existing road node it appears. I erased a city map of all roads with a genuine attempt of overhauling the entire city, I could not lay a new road down after. I decided to recreate the city from an older save.. and was able to lay roads, but only when connected to an existing road. There should be a tool tip alerting to this fact, or road creation behavior should be considered to be revised or it may frustrate players trying to figure out why they can't use roads after blanking a city's existing street layout.