Just to do the devil's advocate thing: I live in the US, on a quiet,
residential one-way street in an urban area. My two cats are
indoor/outdoor - they have access to the outdoors during the day and
are brought in each evening (they come when I call and every once in a
while we have a bit of a chase, but the call of dinner always wins out
in the end). I do worry, of course, but they're both doing well.

I do think 24 hour outdoor access can be asking for trouble, but not
everything needs to be so black and white. One cat, who is hyper and
super-intelligent really does need the outside - she goes bezonkers in
the house from lack of stimulation and loves being outside. I couldn't
bear to take it from her. She only sleeps about 8 hours a day, if
that, and she just gets bored inside. The other cat, a former feral,
can take or leave the outside, but is happy enough to while away the
day chasing butterflies behind her favorite bush.

On our block, there are about 8 owned cats that roam around, and all
of them come around periodically to interact with my two and they all
seem to be doing OK. None of them have dissappeared or gotten hurt and
I see them all the time so no - not all US cats live exclusively
indoors by any means, although many people, like me, do restrict the
outdoor time somewhat.

It depends on what your cat wants and needs. They do have different
personalities and some are more content as indoor cats than others.
You're the best judge of what your cats needs are. The busy street is
a problem. Mine rarely cross the street, if ever (they are discouraged
from doing so), but when I've seen explorer cat do it (once), she did
look to see if any cars are coming.
(It's a one way street and not heavily traveled - which helps).

My neighborhood is cat-friendly and animal-friendly. Everybody knows
the cats and we pet each others when they visit. The only wild animals
around - skunks and raccoons - are only an issue at night when my cats
are inside.

Nothing is guaranteed of course, although it helps knowing that the
vast majority of my neighbors WOULD brake for a cat and WOULDN'T leave
antifreeze congealed on the pavement, but I know that at least one of
my cats would rather live 10 years outside than 20 inside all of the
time. She shows me that everyday. (And very forcefully when I have
tried to keep her in). It's not the life she wants. And in the end,
loving any being is respecting their choices, not just locking them up
to keep them safe.

She's well-trained, she's bright, I supervise her when I can and the
rest of the time I just hope for the best. So far, so good.