This Unreal Engine Plugin will import OpenStreetMap roads and buildings into UE4. You can export OSM data from OpenStreetMap.org 58, drag and drop it into Content Browser to save it as an asset. There’s also a very simple Street Map Component that you can use to render cities.
This plugin allows you to import OpenStreetMap XML data into your Unreal Engine 4 project as a new StreetMap asset type. You can use the example Street Map Component to render streets and buildings.