illegal as in, it is substantially illegal for anyone to alter the built environment to make it more walkable/bikeable -- be it landowners or the local government. because of strict zoning/planning regulations, outdated road design manuals, parking requirements, etc. car-dependency is encoded into law, in the sense that the system is set up so that the default outcome always results in car-friendly development, while any attempt at pedestrian- or cycle-friendly development is subject to arbitrary delays, legal challenges, and needs discretionary exemptions. example: it has been known for decades that Dutch-style intersections[1] are safer than status quo designs, but until very recently it was an odyssey to get one built in the UK or the US, because the transportation authorities have not-invented-here syndrome and won't listen to empirical evidence from abroad (which undermines the claim of traffic engineering to be a scientific discipline). hell, sometimes they'll insist on a "pilot study" even when a design has been a success elsewhere in the same country! but building a junction with inadequate pedestrian and cyclist amenities is easy, so long as it meets safety standards for motorists.
another example: the law says you need to build X amount of car parking spaces in a development, but demands no amenities for cycle storage. or, this[2] disgusting litany of regulatory excuses for why a pedestrian crossing outside a school wasn't allowed be made safer, because nothing can be allowed to reduce traffic speed.
furthermore, in some places the law as written really does de facto criminalize safe cycling. for instance, requiring that cyclists never stray out of the bike lane, even when it contains dangerous obstructions[3]. or, traffic lights that don't detect cyclists, so the lights stay red forever, so it's impossible to proceed without either breaking the law or waiting for a car to come up behind you and trigger the sensor. there are many cases like this -- the law doesn't literally say "you can't cycle", but following the law rules out cycling in any safe and practical sense.
and then there's the absurd fake crime of "jaywalking" ...
another example: the law says you need to build X amount of car parking spaces in a development, but demands no amenities for cycle storage. or, this[2] disgusting litany of regulatory excuses for why a pedestrian crossing outside a school wasn't allowed be made safer, because nothing can be allowed to reduce traffic speed.
furthermore, in some places the law as written really does de facto criminalize safe cycling. for instance, requiring that cyclists never stray out of the bike lane, even when it contains dangerous obstructions[3]. or, traffic lights that don't detect cyclists, so the lights stay red forever, so it's impossible to proceed without either breaking the law or waiting for a car to come up behind you and trigger the sensor. there are many cases like this -- the law doesn't literally say "you can't cycle", but following the law rules out cycling in any safe and practical sense.
and then there's the absurd fake crime of "jaywalking" ...
[1] https://www.youtube.com/watch?v=FlApbxLz6pA
[2] https://twitter.com/LoganTMillsap/status/1583247772509032448
[3] https://www.youtube.com/watch?v=bzE-IMaegzQ