I think that you will find that the ‘sidewalks’ on most of the MTO’s overpasses of Highway 417 are NOT actually sidewalks. They are simply curbs with raised shoulders for snow storage. The areas do not meet the minimum requirements for use as sidewalks. In fact, since the City can’t plow most of them (since they are too narrow for the sidewalk plows), the City has been known to simply put up “NO PEDESTRIAN” signs to try to prevent people from using those bridges to cross the 417. For example, in 2015, right after the MTO reconditioned the structure, if you wanted to walk over the Eagleson Bridge to get to OC Transpo’s Eagleson P&R, during the winter, you would be met with such signs.
(From
Ottawa Citizen article)
When the bridges were first designed/built, they were provided to get vehicles over the 417. They matched the road layout at the existing railway crossings that they replaced. The times were such that pedestrian used the road side to cross the tracks. Since there were no sidewalks beside the roadways, it was deemed that sidewalks were not required on the bridges. Pedestrian crossing of the overpasses was considered exceptional and not really planned for. Recall that, back then, most roads outside of the city core were built without proper sidewalks. Children were taught, in school, the safest way to walk on roads (by Elmer the Safety Elephant). And how to cross railroad tracks (Stop, Look, and Listen).
But those were the days when people were expected to take some personal responsibility for their actions. It was dangerous times; where (older, more responsible) children were even given the (unpaid, except for maybe a movie at the end of the year) task of getting young children safely across busy streets. (Was anyone else a ‘School Patrol’?)
Of course, now it is unacceptable to have such ‘dangerous streets’. The City is continually trying to make the city safe by making ALL streets 'Complete'. Gradually, as the 417 overpass structures are replaced, if the City pony’s up the extra cost, the MTO will install wider structures which include active transport facilities. Note though, that if the City doesn’t pay the additional cost, the MTO is not responsible for anything more than a functional replacement for the (narrow) structures - just as it only replaced what existed when the bridges were first built.