Problem with Roads

I'm playing v1.1 as Makedon, I've conquered all of Greece and Turkey.

All of my Grecian provinces have paved Carriage Roads or better, except Pella, Tylis and Demetrias, and I have no option to upgrade the roads.

Pella and Tylis have less than 5000 residents, and Demetrias has just over 5000. Do they need to have more residents? I figured it might be the kind of Government, but all those places have Type I Governments, and lots of places with Type II and III Governments have paved roads. Any help would be appreciated.

Paved roads become available at city level, 6000 inhabitants.