I didn't know TPMS is mandatory in US and EU about a decade ago. It's still not mandatory in Japan so most cars except luxury or imported don't equip it. Maybe vehicle inspection program (shaken) for every two years helps to avoid using worn tires. Also maybe due to less people use run flat tires than US/EU, or roads in Japan is better.

And I'm not sure what kinds of pressure sensors cars use, but I can tell you the ones I need have been impossible to source for months.

TPMS works by calculating the RPM of the wheel and knowing the tire size and vehicle speed. Most TPMS setups don't know the actual pressure, they infer it.

Both types of systems exist, but from what I've seen the indirect TPMS systems you're describing are becoming less popular. I'm somewhat familiar with Mazdas anyhow and that's the way it's going with them.

For 2017 the Mazda6 used an indirect system: https://www.mazdausa.com/static/manuals/2017/mazda6/contents...

For 2020 it's a direct system with in-tire sensors: https://www.mazdausa.com/static/manuals/2020/mazda6/contents...

This is true of cheaper cars, like my Honda. German cars like Audis and Porsches have direct TPMS that can actually tell you the exact tire pressure.

Most Audis have indirect systems, but they have direct TPMS as an optional extra. At least that's the case on the European market, unsure about the US market. Some premium Audis also have loose wheel detection, which is based on a similar technology as the indirect TPMS.

Oh, interesting. Well, my car at least has sensors—either that or I paid way too much for valve stems. :)

And rear view cameras

Maybe we should amend/change those laws back.

Perhaps we shouldn't.

The EU estimates that half the fatalities on the road will be prevented with these systems. That's 10.000 lives each year. If that's true, increasing the cost marginally is more than worth it (and it really is marginally, budget cars have not noticably increased in price).

They probably estimated from behind a desk to justify some activity, not by research. Over 90% of the fatalities on the road in my country, that has the highest numbers in EU, come from excessive speed and ignoring road laws, something no current safety systems can change. Even airbags are completely useless in a front collision at 150km/h.

Good news, the EU realizes that as well. Starting May 2022 all new cars sold in the EU need to support Intelligent Speed Adaptation: https://www.cnet.com/roadshow/news/european-union-speed-limi...

> budget cars have not noticably increased in price

Actually, they did. The new Dacia Logan starts at 8500 euros, back in 2009 you could buy an entry-level one at about 5500-6000 euros, which would be around 6400-7000 euros in today's money. At those entry level prices those extra 1500-2000 euros do count.

Those systems are good for idiot-proofing. You don't want some idiot with underinflated tires running off the highway. In the same way, you don't want them to back over your kid in a parking lot.