London's roads are not beefed up at all however. There are no 6 lane arterials, and many 4 lane roads lack a centre turn lane, causing a lot of backup in the left lane when someone is trying to turn left. Only 3 intersections have partial double-left turns as well, and many many more are needed. One dedicated left turn lane for buses does exist however.
...There is a super short 6 lane stretch on Wellington by Victoria Hospital, but this is being changed to 4 lanes + 2 BRT lanes.
When I see people like Not Just Bikes making fun of London for it's stroads, we're really not a good example to use. Sure there are some 'stroady' stretches but they're pretty small/tight compared to where you see elsewhere. Our neighbours Windsor and Waterloo Region both have expressways, 6 lane roads, and some spots where the centre turn lane is wide enough to handle a car in each direction. Ex here's Dougal Ave in Windsor:
A major road. Compare that to Wharncliffe Road in London:
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Both have the same suburban commercial plazas and stuff on each side, and I'm sure the two handle similar traffic volumes too.