> Firstly, cars are getting significantly better as they go electric. Smell is eliminated, while noise and environmental impact will be significantly reduced - without any changes to our road infrastructure.
The issue with the road infrastructure is also that it necessitates cars to begin with. With wide, sprawling networks of roads where motor traffic is too fast for people to comfortably walk and cycle, you end up with huge amounts of suburban sprawl. Things are located far apart; tons tons tons more infrastructure needs to be built to provide roads, water, electricity, gas, Internet, police, fire response, schooling and wastewater treatment to those people living in sprawling exurban developments. All the parking lots and strip malls and highways mean that it is simply impossible to make a trip by any way other than car, which triggers orders of magnitude more motor vehicle trips of orders of magnitude longer distance than in a mixed-use walkable neighborhood, so it's not even really useful to draw a comparison between the marginal emissions of four people in a Tesla vs. the amortized emissions of four people on a train.
> Technologies like automatic emergency braking that always watch out for pedestrians and bikers is now standard, and will continue to improve as cars become more autonomous.
I hope this will save lives, but it will never be enough to break the environment of fear and the lurking danger of death that comes with navigating cities with motor traffic, especially since you can never assume that a car is equipped with it (and that it will function correctly). You need to have an incredibly high level of trust, one that just doesn't exist when you are interacting with someone using a different means of spatial displacement. Bikes and scooters are light, slow, small, maneuverable, and offer such good visibility, both to and of the cyclist, that every single risk factor is extremely low.
Or to put another way: in the aggregate it will save lives, but will you always be able to count on it to save yours?
There are other considerations too: a person in any vehicle can, and (in my experience) many do, park or drive in bike lanes or fail to yield to bike lane traffic when making turns. Here you have not the physical threat of the car itself but the fact that by doing this the motorist can force other people to execute dangerous maneuvers, like merging into high-speed motor traffic, splitting the lane or hopping onto the sidewalk to avoid the car.
And as for noise - firstly the tire noise is still there and actually worse due to vehicle weight. The honk is still there, it is still loud enough to trigger a bystander's fight or flight response, and hoo boy is there a lot of it! The people driving in DC and NY seem endlessly upset about the fact that they are doing so.
> In the US, average weight of cars is basically the same as it was in 1975, and per-capita pedestrian deaths have halved over the same period.
There is a lot going on with these numbers. For one, the main cause of this trend was the mass adoption of cars: people are simply walking a lot less than they did half a century ago. For two, the downward trend has sharply reversed since 2009: pedestrians deaths are rising very quickly, rising 50% between 2009 and 2020[1], coinciding modestly with the rise in popularity of mass market pickup trucks and SUVs.
[1]https://www.statista.com/chart/17194/pedestrian-fatalities-i...