Tested in Standard r4072 with Pak128.Britain (Standard, latest binary release), the ordinary player can build the city road from the road building menu.
No bug: as long as the city road has an icon image defined in its pak, it can be built as all other ways. The city road with sidewalk can be build only by public player, there the icon is defined in the entry in menuconf.tab.
Hmm - has this changed recently?
Imho no.
Odd. I'm sure that it's only very recently that it's been possible to build city roads in Pak128.Britain, and yet I don't think that there's recently been a city road icon added.
It's been in pak128.Britain for a long time - I got annoyed at having to change to public player to build city road, so I allowed it for all players in the pak.