To the question of to what degree safety improvements can trigger a rise in bicycling, I would like to add these thoughts based on my experience at the Secret City.
I spent nearly a year among 15,000 other people, mostly servicemembers, in a desert location. I went out every other afternoon to bicycle around the back of the airfield, fighting the north wind constantly. I would race the jets taking off on the runway just a couple hundred meters off to my left. Parking was a dream, with wooden racks placed in front of every destination. I even used a cable lock!
Bicycles were plentiful, mostly department-store mountain-bike models. Private motor vehicles were forbidden. All drivers needed additional layers of certification beyond a traditional US drivers’ license before they could get out on the road. Crashes were investigated thoroughly and those at fault were held accountable. It sounds like an idyllic paradise for bicycling, and in many respects, it was, except for mode share: there were never more than 5% of the people bicycling.
I think this can be largely explained by noncommissioned officers’ reluctance to let servicemembers move around without accountability, and part in the servicemembers’ reluctance to move around without being correctly accounted for. There was no command emphasis on bicycling as an alternative to being driven around in motor vehicles. But in the real world, outside the Secret City, where do the authorities actually promote bicycling instead of other means of transportation?