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Dust from car brakes more harmful than exhaust, study finds

e360.yale.edu

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Re: Dust from car brakes more harmful than exhaust, study finds

#221

Post by BenjiWiebe »

lukevp wrote: post #215
kstrauser wrote: post #207

Earlier quoted context omitted.

Not significantly. Otherwise they’d get hot and work less well. Pads ride very closely to the disc so that road stuff can’t get wedged between the surfaces, and so that you don’t waste break pedal travel just getting the pads close to the surface. Well adjusted drum brakes should be arranged almost exactly the same way. From https://mechanicswizard.com/how-close-should-brake-pads-be-t... : > Typically, the optimal ga…

Are you familiar with how disk brakes on a car operate? They’re essentially a hydraulic piston clamping the brake pads against the rotor. When you let off the brake pedal, the pressure is removed, but there’s not a “retraction” of any kind. So there’s no pressure but nothing is actually making that gap. That article was articulating basically that the piston, when not compressing the brake pads, should not be too far…

Ya but they don't get hot when not applied, which means they're not wasting (much) energy.

Re: Dust from car brakes more harmful than exhaust, study finds

#222

Post by chongli »

bfgeek wrote: post #187
chongli wrote: post #151

Earlier quoted context omitted.

You quoted me out of context by cutting off a very important qualification to my statement: given the same tires on each vehicle I don’t endorse the broader statement which would imply the same wear regardless of tire material. That claim is clearly false.

The point I was after to make is that you can't assume that road wear scales the same way as tyre wear (I was assuming same material fwiw, just different loads). They are being worn under very different modes/scenarios.

Given that roads and tires experience the same forces under driving conditions (Newton’s Third Law guarantees this) I think it’s a reasonable prior assumption to start from. There are of course other environmental factors that accelerate road wear (rain and water erosion, freeze thaw expansion) but those conditions were not included in the study that produced the Fourth Power Law.

Re: Dust from car brakes more harmful than exhaust, study finds

#223

Post by linsomniac »

melling wrote: post #217
hypercube33 wrote: post #206

Earlier quoted context omitted.

Rubber still wears off tires though so that may be worse or not for heavier vehicles

Worried about heavy vehicles? The best selling vehicle is the Ford F-series.

Which is 4,500-5,500lbs curb weight, just FYI.

Re: Dust from car brakes more harmful than exhaust, study finds

#224

Post by leipie »

caycep wrote: post #212
orev wrote: post #88

The Yale article and the paper both highlight the fact that EVs use regenerative braking and produce less dust. I was worried that this was a rehash of the astroturf campaign from a few years ago focusing on EV weight and how that was so bad for the environment because of tire and road wear. Unfortunately you need to read through the whole thing (instead of the headline and a few paragraphs) to see that information.

Granted, I would still rather them designed for lighter weight. But that’s a separate issue w suv culture which is bad for society and environment in general. Totally would buy a 3000 pound EV around the size of a euro hatch.

My Citroën C-Zero (Mitsubishi i-MiEV clone) is a quirky fun car to drive. Surprisingly big on the inside. Very plain old skool car. Just turn the key and go. No dumb computers/dashboard in it trying to smart. I bought it for 4000 euros second hand. Only down side it had an original range of ~120km and it has 120000km on the clock. The battery is down to 60km range, after those ~1500 cycles... But aftermarket batteries with for the original range are now available for "just" 11000,- If they would build a modern version of it, I would buy it.

Re: Dust from car brakes more harmful than exhaust, study finds

#225

Post by [deleted] »

caycep wrote: post #212
orev wrote: post #88

The Yale article and the paper both highlight the fact that EVs use regenerative braking and produce less dust. I was worried that this was a rehash of the astroturf campaign from a few years ago focusing on EV weight and how that was so bad for the environment because of tire and road wear. Unfortunately you need to read through the whole thing (instead of the headline and a few paragraphs) to see that information.

Granted, I would still rather them designed for lighter weight. But that’s a separate issue w suv culture which is bad for society and environment in general. Totally would buy a 3000 pound EV around the size of a euro hatch.

[deleted]

Re: Dust from car brakes more harmful than exhaust, study finds

#226

Post by Aromasin »

caycep wrote: post #212
orev wrote: post #88

The Yale article and the paper both highlight the fact that EVs use regenerative braking and produce less dust. I was worried that this was a rehash of the astroturf campaign from a few years ago focusing on EV weight and how that was so bad for the environment because of tire and road wear. Unfortunately you need to read through the whole thing (instead of the headline and a few paragraphs) to see that information.

Granted, I would still rather them designed for lighter weight. But that’s a separate issue w suv culture which is bad for society and environment in general. Totally would buy a 3000 pound EV around the size of a euro hatch.

I recently just sold on my old car, as I'm getting a company one. Figured it'd be some estate or coupe with good motorway mileage. Nope. Instead it's an SUV, which I've routinely given people shit for, for the last few years. The things are a plague that are starting to infest even corporate motor pools, and this is in the UK of all places, where the country roads are more often than not the width of a small hatchback.

Re: Dust from car brakes more harmful than exhaust, study finds

#227

Post by oftenwrong »

According to this 2020 paper, "resuspended" particulate matter may be a major, previously unaccounted-for contributor to pollution from roads.

https://www.mdpi.com/1660-4601/17/8/2851

>Traffic-related resuspended dust is particulate matter, previously deposited on the surface of roadways that becomes resuspended into the air by the movement of traffic.

>Results show that the inclusion of resuspended dust in the emission and dispersion modeling chain increases prediction of near-road PM2.5 concentrations by up to 74%.

The weight, speed, and volume of traffic, are therefore considerable factors even beyond the pollutants the vehicles leave behind.

Re: Dust from car brakes more harmful than exhaust, study finds

#228

Post by AnthonyMouse »

Earw0rm wrote: post #166
AnthonyMouse wrote: post #134

Earlier quoted context omitted.

Speed limits are set for the conditions, e.g. they're lower in an area with high pedestrian traffic than on the highway. But that's just dodging the issue; what do you do about the highway? Traveling at higher speeds on the appropriate roads is good and people want to continue to do that. You want plumbers and firefighters to be able to travel quickly from one side of the city to the other. So then you've got a highw…

Plumbers and firefighters have stuff to haul and long distances to cover. They need to do 40/50/60mph on the freeway, and 15/20mph on local surface access roads where they're mixed in with light vehicles. The whole light-vehicle thing is predicated on low speeds and relatively short distances (up to about 15 miles). Most urban areas, even fairly sprawling ones, that's enough to cover a pretty substantial % of trips.…

> as soon as you get to about 25-30mph you need impact protection, and the design constraints quickly escalate to "absolutely no smaller than a Fiat 500".

The real problem here is that as soon as you need impact protection, you get four wheels, and then it's classified as a car instead of a motorcycle and the government safety standards for cars de facto require "absolutely no smaller than a Fiat 500".

What would be interesting is to change the definition of "motorcycle" from "has fewer than 4 wheels" to "has fewer than 3 seats" and see what happens.

Re: Dust from car brakes more harmful than exhaust, study finds

#229

Post by ghaff »

mschuster91 wrote: post #125
oliwarner wrote: post #71

Earlier quoted context omitted.

Firstly, this is another positive for EVs. They do have brakes but most have regenerative braking too, which is clean. Secondly, ebikes are rampantly misused in pedestrian areas, often used without helmets, often upclocked, many used for delivering, or kids. And because they're not a regulated vehicle, nobody has third party insurance. There are legal ebikes and nobody has any more of a problem with them than normal…

> And because they're not a regulated vehicle, nobody has third party insurance. At least here in Germany, assuming it's not a tuned bike, it's covered by your regular liability insurance.

In the US at least, I'm not sure what "regular liability insurance" means. Might be something on a homeowner's policy and something on auto insurance but it's probably not something the average person necessarily has.

Re: Dust from car brakes more harmful than exhaust, study finds

#230

Post by thaw13579 »

bluescrn wrote: post #210
light_hue_1 wrote: post #191

Earlier quoted context omitted.

Are you replying to the right post? My default is my manual bike. No amount of infrastructure will make these electric motorcycles safe in bike lanes or pedestrian paths. They should be banned.

We don't ban cars or motorbikes because they're unsafe. We require a license and insurance then ban those who repeatedly break the rules of the road. We need to find a sensible way to regulate these bikes, which may involve some sort of license, insurance, and mandatory helmets. But it needs to be less costly/more convenient than getting a petrol motorbike (or car) if we want people choosing the more eco-friendly opt…

I think the parent is talking about banning them specifically in pedestrians and cycling lanes. We currently ban motorcycles and cars from using them, presumably because it’s dangerous to pedestrians.
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