[ok-repl]

I think lot of people here are going to disagree with me but seems to me there's a case for putting limiters on cars.

Drivers sometimes hit other vehicles. Airbags go a long way here. Sadly, drivers will often hit less fortunate road users such as pedestrians and cyclists.

We already know that pedestrians hit at 30 km/h vs. 50 km/h stand a much better chance to survive. Sadly, cities are rarely designed for 30, and usually more 50+, depending on the city.

Changing cities is, well, possible, but also kind of difficult and unpopular. You know what's easier? Making car manufacturers limit cars' speeds in cities.

It's not technologically difficult. Lots of new cars already read speed signs. Almost all of them have some sort of GPS component.

Geofencing speed limits seems like a pretty easy fix compared to the infrastructure changes of traffic calming (which we should do anyway). You can make it opt-out (and non-trivial enough to do so) so that most new cars on the road have these limits at least in cities.

Does this sound crazy? I'd argue it isn't. Consider that E-bikes/E-scooters are limited to 25km/h in a lot of countries. Similar story with small 50cc scooters. In some places rental E-scooters even have geofenced speed limits already, and the Netherlands is considering a similar plan for E-bikes (ones owned by ordinary citizens).

[falcolas]

While this is theoretically a good idea, in practice there's a lot of hard questions without good answers.

Where does a city begin? End?

Should we cover the suburbs with the geofence?

What about the beltways or highways that go through the city?

In big cities, GPS is spotty or completely unavailable, what do we do there?

What about city streets which pass under/over highways?

As I've pointed out in other replies, there isn't a good enough, when forcing cars to slow down significantly. Road conditions and surrounding traffic speeds make any unexpected slowdowns ripe for creating accidents.

[ok-repl]

I don't know where you live but city limits are very clearly defined in many places. Here for example, there are clear designations (that are reflected in a default speed limit too).

I don't quite know what your (American?) suburbs look like, but in theory I don't see why not in this instance.

And if you're concerned about, idk, people not being able to get to the hospital on time or what have you, make them opt-out on every single ignition. Most people will probably not be bothered to opt-out every single time.

As for the technical points regarding GPS, lots of cars already read speed signs and come with various computer vision based safety features.

Again, ebikes and escooters are already speed limited and geofenced. It's not perfect, but why aren't we so concerned about ebikes being slow and not being able to keep up with cars and subsequently be hit by them?

Lastly - it doesn't have to come into full effect if you're at 120km/h. You can be smart about it, like not slowing you down but not letting you accelerate, easing you into the speed limit etc.

There's a perception that cars are a fact of life and it's OK for them to be traveling at speed in cities, whereas the reality is that in most urban areas we simply cannot afford to keep this up any longer.