There's also the possibility of creating separated infrastructure to allow the smaller/lighter vehicle riders (e.g. two/three wheelers) to not have to tangle with car and lorry drivers. However that requires political will and infrastructure investment.
Ironically, the somewhat obvious solution to this would be smaller/lighter cars (e.g. one- or two-seaters), but they can't pass the safety standards required for cars even though they would still be dramatically safer than two-wheeled vehicles.
The whole light-vehicle thing is predicated on low speeds and relatively short distances (up to about 15 miles). Most urban areas, even fairly sprawling ones, that's enough to cover a pretty substantial % of trips.
It's about using 1/10th the weight and 1/50th the power to cover a big % of the same tasks. Personally I'd say the bike/scooter/golf-buggy, and then either an owned or shared car for the last 10% of trips where you need to use the freeway is a better optimum than high-speed light vehicles, because as soon as you get to about 25-30mph you need impact protection, and the design constraints quickly escalate to "absolutely no smaller than a Fiat 500".
There's also ofc the option of mass transit for some of the longer distance stuff, at least in cities that are able to build it.
The real problem here is that as soon as you need impact protection, you get four wheels, and then it's classified as a car instead of a motorcycle and the government safety standards for cars de facto require "absolutely no smaller than a Fiat 500".
What would be interesting is to change the definition of "motorcycle" from "has fewer than 4 wheels" to "has fewer than 3 seats" and see what happens.
The problem seems to be that for most people who can legally drive a full-scale car (i.e. they're not too young or too old) getting a do-everything vehicle on finance is more attractive at that point.
They're somewhat popular with youngsters in rural areas (cheap to insure, minimum driver age is 14 I think, whereas for cars in France it's 17) and with frailer, older people who can't walk or cycle very far and don't have the stamina for longer drives, they just want an inexpensive little runabout to get to the village shops, nearby friends and appointments.
But they're expensive enough (about $10k) that you're unlikely to buy one in addition to your regular do-it-all car, where you might buy an ebike, pedal bike or motorcycle. Maybe as a second vehicle in a childless couple where one partner does almost all the driving, but unless heavier vehicles are highly taxed or restricted (city low emission & congestion zones), there's not enough advantage in one of these for mass adoption.
I've got an ebike in central london and find it quite practical on the whole. For local journeys <2miles it's faster than anything else and you can go down mostly traffic restricted roads. For intercity you can put the bike on a train. Rain is a bit of a pain.
that could be a win for the environment and I guess they replace normal vans. And I just saw a two seater ebike taxi with a roof.
What issue? I would regularly go 50km/h down hills on my road bike. That was completely my choice and if I came off I'd suffer the consequences.
The problem isn't the occupants. Nobody is forced to travel at high speeds (except on motorways). The problem is the people around and the environment. I definitely would not ever go that fast in town, even down a hill, because it's generally not safe for the people around me.
The problem with cars is the huge imbalance of power. Every car has the capability of killing or disabling you. But you can't disable them. As far as I know, carrying a portable EMP device is neither practical nor legal. Two wheeled vehicles don't exhibit this imbalance of power, not even motorbikes. I believe this is the most important reason to get rid of cars from towns.
If you're on a bike, then you should also prioritise your own safety as you're likely to come off worse even when colliding with a pedestrian.
Anecdata time: my brother (over 60 years old and a very experienced cyclist) was heading down a hill, presumably at some speed and a young boy stepped out in front of him. They collided and my brother came off and ended up with a broken collar bone, broken rib, collapsed lung and minor concussion (he's fully recovered now). The kid received no damage apart from bruising AFAIK.
I still don't understand how they expect to solve the occupant safety issue though. Cars travel at high speeds but have crumple zones and airbags. E-bikes travel at the same speeds but if you crash, you die. And 2-wheeled vehicles are easier to crash.
The fatality rate for motorcycles is astonishingly bad and changing the propulsion type wouldn't really affect that.