When you build the smallest 2 lane highway (1 in each direction) you can't use upgrade to make it the version with walls to reduce sound pollution or the one without extra walls. It akways shows "you can't upgrade this road" .
Update : it seems this happens with elevated bridges only. I built it in the air above my normal roads. Looks like there's only one version of the road then.
All DLC, v1.0.5.0
Update : it seems this happens with elevated bridges only. I built it in the air above my normal roads. Looks like there's only one version of the road then.
All DLC, v1.0.5.0