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They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. There's been studies done here in Swede
by kungtotte 7y ago
They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road.
There's been studies done here in Sweden since we've banned studded winter tyres in some areas of Stockholm in an effort to reduce road wear and improve air quality. I don't know of any sources in English off the top of my head though.
The last time I read an article about it though (2+ years ago, during Diesel-gate), the findings was that the danger in the particles comes from their size with smaller particles being more dangerous for humans. And that road particles were something like an order of magnitude larger than exhaust fume particles from diesel engines.
We've since banned diesel engines inside Stockholm as well so the whole thing is moot here.
- blattimwind 7y agoThe studs in tyres are small carbide rods, which will easily chew through a soft material like asphalt. A rubber tyre would seem to be quite a bit softer than asphalt in colder conditions, so I have a hard time imagining the rubber wearing the asphalt down so significantly.
- gentleman11 7y agoI have been wearing studded slip on crampons when walking my dog this winter. The ice has been ridiculous, I’ve fallen twice already when not wearing them. Not great for the sidewalks, I know, but the dog needs his walks or he would... get sad
- gambiting 7y agoI cannot believe a studded shoe would have any impact whatsoever on a concrete pavement. Human weight is nothing compared to that of a car.
- Fjolsvith 7y agoBy your logic, water running across concrete wouldn't create any wear on the concrete, but in truth, it does.
- gambiting 7y agoYeah, but there's a lot of water, and it can run over concrete for hours if not days at a time - of course it has an impact simply due to the sheer volume of it. Again, how does it compare to the miniscule impact of studded shoes?
- ars 7y agoThe ground pressure of a human wearing studded shoes is an order of magnitude or more higher than the ground pressure of a car. The ground pressure of a car is exactly equal to the PSI that you inflate the tire. Take the weight of a human and divide by the surface area of of a started shoe you will find a significantly higher number.
- gambiting 7y ago>>The ground pressure of a car is exactly equal to the PSI that you inflate the tire Wait, what? So if the tire is flat, the car exerts no pressure on the ground? :-P
- ars 7y agoI know you are joking but just to answer the question anyway, if the tires are completely flat then they are not supporting the car and you can't use them for measurement. If the tires are partially flat then they are supporting the car and the PSI is correct and you'll notice the tire spreads out wider on the road so the ground force is lower because it's spread out over a larger area. Technically you have to also include the springiness of the sidewall in the measurement not just the PSI of the air.
- gambiting 7y ago>>if the tires are completely flat then they are not supporting the car and you can't use them for measurement. Run-flat tires are a thing though - you can drive on them even with no internal pressure, there can be a gaping hole in it and you can still drive on them. So what's the pressure the car exerts on the road when driving then?
- ars 7y agoThat's where the "springiness of the sidewall" I mentioned comes in. Normally (with inflated tires) it doesn't play much part. But with flat tires it can come to dominate.
- 7y ago
- labawi 7y agoWeight of a masonry hammer is nothing compared to the weight of a human, yet it can destroy concrete with ease. I'd guess it depends on how and how much you walk on what kind of pavement with what kind of studded shoes. Damage can realistically be imperceptible or ugly.
- runarberg 7y agoThere are a lot more cars, running on much greater speed, for a lot longer distance, with much greater weight, then humans walking on spiked shoes. The masonry hammer runs on much greater speed, with much more force, a lot more often then the human steps on the peace of concrete being taken apart.
- fiblye 7y agoConcrete sidewalks are pretty fragile. Unless they're freshly laid, most that I see have cracks and pits to some extent (probably mostly attributable to cooling/heating and water). Some people also seriously drop their feet down hard when they walk, and if they've got little bits of metal sticking out from the bottom of their shoes, I imagine that damage adds up and doubly so if it slams down an existing crack.
- deleted 7y ago[deleted]
- saiya-jin 7y agoThat doesn't make sense to me either. Take a busy German highway (as I don't know the average load on US ones), easily 100k cars per day. There are parts of highways which don't get replaced for 20 years easily. Plus apart from tiny fraction of north europe (and maybe Canada?), nobody ever uses studs. Back of the envelope math tells me 1 km of highway would lose some 730 tonnes of asphalt, per year (so 14,600 tonnes in 20 years). If we talk about normal car wear, this simply isn't happening on those unkempt roads. It would leave huge lanes of deeper surface where asphalt is lacking. There isn't visible wear on lanes that are used mostly by cars like that. Roads have mostly potholes. What happens on those roads is, sticky asphalt is worn away (but not at the mentioned rate), and what remains are stones which basically don't wear, and tires touch only that. At least highway surface I saw was like that. What damages roads greatly are trucks, especially overloaded ones (say limit is 15 tonnes, they take 22 tonnes and hope to not be checked... welcome to east european mentality).
- loeg 7y agoPeople use studded tires the US, too.
- 9HZZRfNlpR 7y agoAnd Eastern Europe, colder parts of Russia etc.
- Causality1 7y agoA rough way to think about road wear is the weight over one axle to the fourth power times the number of axles.
- na85 7y agoThat gives you a quantity of force^4. How does that translate to road wear?
- cheerlessbog 7y agoEmpirical studies apparently find road wear matches a power law. Although it seems the exponent varies. Here's a survey https://www.nzta.govt.nz/assets/resources/603/RR-603-The-relationship-between-vehicle-axle-loadings-and-pavement-wear2.pdf https://www.nzta.govt.nz/assets/resources/603/RR-603-The-rel...
- labawi 7y agoStudy mentions EU and source company has offices in Stokenchurch, UK and Stuttgart, Germany. I doubt they tested with studded tires and called it typical. They did test with brand new tires - that's the likely source. "Emissions Analytics .. [self proclaimed?] leading independent .. specialist for .. measurement of realworld emissions .. performed .. initial tyre wear testing. .. on brand new, correctly inflated tyres .. [and] found that the car emitted 5.8 grams per kilometer of particles."
- nvader 7y agoI don't think you can call it a study. They say they performed, "initial testing".
- ta999999171 7y agoBANG - thank you. Brand new tires have a molding protectant layer on them. "Scrubbing" is common in auto racing, on a new set.
- toxik 7y agoWe have not banned diesel engines in Stockholm at all?
- ars 7y agoIf the particles were coming from the road then roads would wear in very visible ways. But we don't actually see that kind of wear. Roads don't typically have grooves on them where the cars go that are lower than the middle which doesn't have tires driving over it.
- Reason077 7y ago> "the danger in the particles comes from their size with smaller particles being more dangerous for humans. And that road particles were something like an order of magnitude larger than exhaust fume particles from diesel engines." Exactly. It might look bad when you compare the mass of particles, but if you compare the particle counts, it's exhaust emissions that produce the big numbers - of really tiny (sub-PM2.5) particles.
- bigiain 7y ago>They're torn up from the road and rubbed off from the tyres themselves. The majority is obviously coming from the road. Not sure even that adds up to believable. The Sydney Harbour Bridge is about 500m long between the pylons. It has "more than 150,000 cars per day" on it (according to the snippet from a google search). If all of that was from the road, that'd mean there's about 160 tons of road getting torn up per year. It looks to be ~30m wide on Google Sat view, and "google first hit" research indicates road base weighs 1.9tons per cubic meter. It's be losing almost 6cm of depth along the whole span every year if all those numbers hold, or 3cm per year if "only half" of that comes from the road and the rest from the tires. They don't resurface it anything like often enough for that to be true...
- deleted 7y ago[deleted]
- TheSpiceIsLife 7y agoPerhaps it’s mostly existing particles laying on the road that are thrown up by the next vehicle’s tyres as it passes?
- bigiain 7y agoThat's a pretty long stretch from the claim: "we found that the car emitted 5.8 grams per kilometer of particles".
- JangoSteve 7y agoBut is it a long stretch from the claim: "Non-exhaust emissions (NEE) are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage." Resuspension of road dust is literally one of the 4 things they defined as the NEE they're measuring.
- bigiain 7y agoOK, I missed that bit. But counting "resuspended road dust" as "emissions" seems pretty far fetched to me. Especially if that's a significant portion of the "5.8 grams per kilometer of particles", and you then push out a press release with the hyperbolic headline claim "Pollution from tire wear 1000 times worse than exhaust emissions." And they then have the audacity to claim: "Emissions Analytics seeks to bring transparency to a confused market sector." Pretty sure I know who's funding them now, without even bothering to google it...