Most bridges in Greater Vancouver are so narrow, because there was no provision to have bus and HOV lanes. The+Lion+Bridge+and+The+Iron+Bridge are 2 classic examples of not constructing additional infrastructure to accommodate bus lanes, HOV lanes and especially, rail rapid transit. That's because such improvements would actually go against the congestive urban planning agenda.
https://en.wikipedia.org/wiki/Lacey_V._Murrow_Memorial_Bridge , https://www.historylink.org/file/21298 A narrow 4 lane BC type bridge was upgraded to an 8 lane crossing, plus 2 LRT tracks for WA.
https://en.wikipedia.org/wiki/Narrows_Bridge_(Perth) From a basic bridge to a nice 10 lane crossing with 2 train tracks for WA. https://structurae.net/en/structures/narrows-bridge Its great that the horrible backwards Vancouver mentality never made it to Perth. https://www.abc.net.au/news/2019-11-13/perth-narrows-bridge-60-years-since-construction/11697812 Unfortunately, Vancouver & BC have done their damndest to prevent a similar nice, wide crossing, which also includes 6_car_trains. While backwards Vancouver & BC didn't want to build wider infrastructure simply to accomodate more drivers, the funds didn't seem to go towards a regional rapid bus or at least an express bus & HOV network with its own set of bridges. The SkyTrain should have been designed with a provision to eventually have stations at least as long as those on the Montreal Metro, which can accomodate 9 car trains on a 500 ft platform or 152.5 m. https://heritage.engineersaustralia.org.au/wiki/Place:Constructing_Narrows_Bridges
The old Champlain_Bridge_in Montreal just had 3 lanes each way & no provision for a train. Where as the new Samuel-De_Champlain_Bridge provides 4 lanes each way & has 2 REM train tracks. https://www.samueldechamplainbridge.ca Fortunately, Montreal, like Seattle & Perth was able to have a nice wide bridge with 2 train tracks in the middle. https://en.wikipedia.org/wiki/Samuel-De_Champlain_Bridge#Construction_method
Montreal, Seattle & Perth are allowed to exist on a larger scale than backwards Vancouver, because they don't have the same imposed restrictions. Urban Quebec and urban WA are able to do so much more, because they aren't hindered by anything like the backwards BC mentality.
Risk assessment model of bottlenecks for urban expressways using survival analysis approach https://www.sciencedirect.com/science/article/pii/S235214651730474X
