Thanks for the comment
Federal highways will all be because of the Official Languages Act, while provinces will decide for themselves according to their own legislation. The logo on the e-Boards shows Ontario in this case, and I am uncertain if its province wide or as you mentioned, in certain designated areas. But for this case, seeing that Ottawa is Canada's capital and Gatineau Quebec is just across the river, pretty well everything is bilingual in terms of road signs in the Ottawa area.
Vinny