Oh man, you are the first person to bring up the elderly and disabled. I bet we can't figure that out at all so we better not try.
Or, municipalities continue to provide on demand transit using small vans to the elderly and disabled, since no one said there can't be exemptions to the car free rules.
Perfect so now you still need perfectly functioning roads and traffic infrastructure, but only use it at 1% capacity while the public transports are completely over-capacity.
Come on, can't you imagine that people would CHANGE their habits if their environment changed? We wouldn't make the same kind of choices about where to go, where to put businesses, how to move around, etc.
Incentives matter, but the effect is never what you want.
Put more bicycle lanes up and people will buy mopeds (which polutes like crazy), or take jobs elsewhere, or something else crazy.
A good example is probably Australia where they made helmets mandatory for adults on bicycles. So many more people choose to take their car that the number of saved lives were offset by the amount of exercise lost.
So, helmet laws are actually a terrible example of "effects aren't what you want", at least, it's a terrible example if the implication is that we are getting an effect that we don't expect. Now, it's possible that the legislators didn't understand this, but cycling advocates were and are well aware that helmet laws cause reduced bicycle use. Here's an article with sources which claims to be from 2006, the website copyright notice is 2013, so at the very least, it's from right around when Australia implemented it's helmet law. http://bicycleaustin.info/laws/helmet-laws-bad.html
Cycling in Australia dropped by about 2% between 2011 and 2013. [1] The biggest issue with helmet laws though is that they significantly neuter bike share programs because people don't want to cary a helmet or use a shared helmet.
I know that there are unintended consequences of everything. You have to have the courage to reevaluate your choices, not just make a change once and then be done forever.
Making one mode artificially suck is not the right way to go about it. City bikes (Velib) were an awesome initiative and I use them every day, not because I don't want to use a car, simply because it's the best mode for most of my movements.
The goal should be to have a wide array of choices and let people choose the best mode for their needs and their means, not to choose for them.
If the only vehicles using the road are public transit vans, we can clearly reduce the size of roads and the infrastructure. The vastly reduced wear and tear on the roads would free up government money for investment in public transit.
