Problem with Roads

[Madoushi]

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.

[Taedius]

Paved roads become available at city level, 6000 inhabitants.