Bicycles aren't unsafe in themselves, see lots of cities where cycling is a very common and safe mode of transportation. Scooters on the other hand are indeed a lot less safe due to their small wheels, short wheelbase and awkward stance of the rider. That said, it's the urban planning that makes cycling unsafe in many places, not the device itself.
(Why am I using >50 km/h as the benchmark? Because that's the sort of speeds you easily end up at if you try to keep up with cars downhill.)
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Edit: it seems that people are missing critical words in my comment:
- "Ordinary upright/city bike" means "not road/touring/etc bikes". They are constructed differently and comfortably do well over 50 km/h.
- "Downhill" means significant gravity assistance for a few seconds up to a minute, and not "sustained under pedaling power alone". I'd be impressed if you regularly did 50 km/h on the flats with one of those bicycles.
Who on earth is using ordinary city bikes at 50km/h near cars? Even class II e-bikes are limited to 20mph/32kph.
Class III are limited to 28mph/45kph but are forbidden from bike paths.
[edit] 50kph under your own power is the average speed at the Tour de France.
My bike was quite stable at 40mph.
No I wouldn't go that fast on a bike path, this was only due to the power of gravity.
Now, I fully agree with the spirit of your post. Even the spots I'm talking about are short bursts.
Not many people will do >50kmh even downhill (even with disk brakes), and on the few occasions I've done so, I absolutely would not say there are "significant controllability problems". In fact, quite the opposite.
[1]https://www.youtube.com/watch?v=FN6Z8UgVOuw Nb - these were shot in the days before the 'supertuck' (sitting on the crossbar) was banned.
Bicycles with helmets are fairly safe. Without helmets? No way, I'm not riding without a helmet. But scooters without helmets are much worse, I wouldn't dare go much more than 10mph on a scooter without a helmet.
It's entirely possible to ride a bike in a way that actually doesn't require a helmet. It's VERY boring :-P , but nevertheless practical and doable.
I've fallen a few other times besides those two, but those are the worst two and I think without a helmet I would have been seriously injured if not dead.
