Air pollution fell substantially as Paris restricted car traffic • Hacker News Board

Re: Air pollution fell substantially as Paris restricted car traffic

#101

Post by bornfreddy » Sat, Apr 12, 2025, 6:24 PM UTC

ahaucnx wrote: post #83

10-1-100 wrote: post #16

Earlier quoted context omitted.

Also worth noting that with modern emissions standards (and transition to EVs), over 50% of handful particulates come from tires, brakes, road surface wear, and resuspended dust: https://www.oecd.org/en/publications/non-exhaust-particulate... I don't think there's any healthy level of private cars coexisting with humans in a city, without even considering the more immediate harms from crashes, etc.

It seems that there has been fundamental mistakes and overstatements in the amount of particles from brakes in much of the secondary research in the last decades. Details: https://pubs.acs.org/doi/10.1021/acs.estlett.4c00792

One would also expect that EVs wouldn't emit that many particles from brakes since the brakes typically wear much more slowly than with ICE cars.

Re: Air pollution fell substantially as Paris restricted car traffic

#102

Post by Tade0 » Sat, Apr 12, 2025, 6:24 PM UTC

1over137 wrote: post #61

EA-3167 wrote: post #44

Earlier quoted context omitted.

Not just horse poop, but dead horses that were quite the chore to remove back in the day, and the danger posed to pedestrians by a bunch of quite large and easily panicked animals.

We still have that danger. But the animals are homo sapiens and they are surrounded by 2 tonnes of metal. :)

One of the early examples of the Poisson distribution was the rate at which soldiers in the Prussian army would be fatally kicked by horses.

Translates to a little over 30 deaths per year per million, so not a lot, though I suspect the number would have been much greater adjusted for distance travelled and even without that it's more than some countries achieve with their traffic.

Re: Air pollution fell substantially as Paris restricted car traffic

#103

Post by basisword » Sat, Apr 12, 2025, 6:25 PM UTC

10-1-100 wrote: post #16

bri3d wrote: post #12

Worth noting that 50-60% of passenger cars in France are diesel, but Paris have been gradually banning older higher emission diesels (Crit’air 3, 4, 5) from Paris. Banning cars outright also works, of course, but I suspect a lot of the reduction can be attributed to getting particularly bad diesel cars out vs. the limited areas where cars are entirely restricted.

Also worth noting that with modern emissions standards (and transition to EVs), over 50% of handful particulates come from tires, brakes, road surface wear, and resuspended dust: https://www.oecd.org/en/publications/non-exhaust-particulate... I don't think there's any healthy level of private cars coexisting with humans in a city, without even considering the more immediate harms from crashes, etc.

There are lots of things in cities that are unhealthy for both ourselves and others but we allow them. It's possible to make big improvements while still enjoying a certain amount of the benefit of something.

For example - if you use the London Underground the air you breathe in is significantly worse than the air above ground in busy traffic. Significantly.

Re: Air pollution fell substantially as Paris restricted car traffic

#104

Post by loloquwowndueo » Sat, Apr 12, 2025, 6:26 PM UTC

Saline9515 wrote: post #100

oblio wrote: post #50

Earlier quoted context omitted.

Let's be real here, a huge chunk of car traffic in cities is purely for convenience. Once that's reduced by say, 50%, everything becomes much better, but nobody gives up convenience voluntarily.

The problem is that, among casualties, you create an environment that is hostile for families and disabled people.

Only if you just remove the cars without replacing them with good public transportation (family friendly, accessible, with special modes for disabled people).

Re: Air pollution fell substantially as Paris restricted car traffic

#105

Post by timewizard » Sat, Apr 12, 2025, 6:27 PM UTC

grg0 wrote: post #31

Cars in cities, let alone designing cities around cars, is one of the greatest tragedies of modern life.

There are cities not designed around cars. We just call them "rural." You could not have had your urban city without cars. There is absolutely nothing "tragic" about this.

Meanwhile you live in a world where petty wars are fought over resources to enhance the wealth of an extreme minority of the population. That's an actual tragedy.

Re: Air pollution fell substantially as Paris restricted car traffic

#106

Post by chadd » Sat, Apr 12, 2025, 6:29 PM UTC

Saline9515 wrote: post #100

oblio wrote: post #50

Earlier quoted context omitted.

Let's be real here, a huge chunk of car traffic in cities is purely for convenience. Once that's reduced by say, 50%, everything becomes much better, but nobody gives up convenience voluntarily.

The problem is that, among casualties, you create an environment that is hostile for families and disabled people.

i'm not sure this is true, for instance NYC ranks as the second most disabled-friendly city

https://www.amny.com/lifestyle/new-york-city-ranks-2nd-in-a-...

Re: Air pollution fell substantially as Paris restricted car traffic

#107

Post by freen » Sat, Apr 12, 2025, 6:29 PM UTC

timewizard wrote: post #105

grg0 wrote: post #31

Cars in cities, let alone designing cities around cars, is one of the greatest tragedies of modern life.

There are cities not designed around cars. We just call them "rural." You could not have had your urban city without cars. There is absolutely nothing "tragic" about this. Meanwhile you live in a world where petty wars are fought over resources to enhance the wealth of an extreme minority of the population. That's an actual tragedy.

It seems we have very different definitions of “city”.

I am very curious to hear yours.

Re: Air pollution fell substantially as Paris restricted car traffic

#108

Post by thehappypm » Sat, Apr 12, 2025, 6:29 PM UTC

FredPret wrote: post #90

trollbridge wrote: post #64

Earlier quoted context omitted.

But spews forth more rubber (and plastic, since that's what tyres are made from these days), which is an ongoing problem for Tesla EVs when owners discover their tyres don't last nearly as long because they're transmitting power both when starting and stopping, not just when starting.

It’s because they weigh more

“They weigh more” is something I kinda have a problem with. People act like EVs are these behemoths, but your typical EV is hardly an outlier. The Tesla Model 3, for example, weighs as much as a Honda CRV. Yes, that’s a different car class; but nobody looks at a CRV and complains about its weight and the environmental impact of that weight on air quality nearly the same way.

Re: Air pollution fell substantially as Paris restricted car traffic

#109

Post by appreciatorBus » Sat, Apr 12, 2025, 6:30 PM UTC

graemep wrote: post #78

pluc wrote: post #38

Don't have to ban cars - the UK has adopted a speed limit of 20/30 mph in cities and I'm sure it helps. Surely helps with the noise and the safety

It can make pollution worse. ICE cars are most efficient at around 50mph.

> ICE cars are most efficient at around 50mph

... when driven continuously without stopping, like a on cross country limited access highway.

When driving in the places people live, with cross walks and stop signs and children playing outside requiring frequent slowing & stopping, there's no efficiency benefit from racing 0 to 50mph every block then slamming on the brakes, only to repeat for each block after.

Re: Air pollution fell substantially as Paris restricted car traffic

#110

Post by flomo » Sat, Apr 12, 2025, 6:31 PM UTC

bri3d wrote: post #73

trollbridge wrote: post #71

Earlier quoted context omitted.

It's due to the regenerative braking, which transmits more power via the wheels when decelerating. Most ICE cards don't have regenerative braking; hybrids tend to.

This doesn't make sense. Energy in the system is conserved. On an ICE car, brakes convert the energy to heat. On an EV, motors convert the energy to electricity. The tires experience the same net force. EVs wear tires more quickly, in general, because they are very heavy and produce more torque (and drivers are more likely to request that torque, also).

I'd guess an ICE transmission provides some deceleration too. But right on, apples-to-apples you would need to compare a Tesla to a Mercedes or etc and not a Corolla. They are sold as a luxury/performance car.