5 ms·

And we need more lightweight cars , not heavier, since tire wear is proportional to vehicle weight to the fourth power. Ironically, CAFE regulations and EV inc

And we need more lightweight cars , not heavier, since tire wear is proportional to vehicle weight to the fourth power. Ironically, CAFE regulations and EV incentives both did the opposite

kijin 2y ago
> tire wear is proportional to vehicle weight to the fourth power. Does this mean that a bus that weighs 10 times as much as a small car will produce 10000 times as much tire dust? If it does, I'm not sure if investing in buses will reduce tire dust at all. A bus can replace a lot of cars, but 10000 is a stretch. We need more trains.
- deleted 2y ago
  [deleted]
- penjelly 2y ago
  trams were popular in tons of places before, I understand they improved traffic significantly compared even to today, and they'd still have a positive effect now, I think. But most places shifted towards a car centric focus and we lost those.
- zamadatix 2y ago
  I think the root observation here comes from https://en.wikipedia.org/wiki/Fourth_power_law https://en.wikipedia.org/wiki/Fourth_power_law which really talks about the inferred stress to the road for given weight on the axle, not tire wear based on vehicle weight. The above seems to be using a simplification based on passenger cars staying with 4 tires across 2 axles but how this relates to tire wear is going to be a bit more complicated when you start talking about vehicles which can have more axles, more tires per axle, and significantly larger tires. I'd believe buses have a lot of tire wear compared to an individual car but I wouldn't use that relation as proof of just how many times so.
ethagnawl 2y ago
I'm not sure why you're being down voted for suggesting a practical and fact based solution. The USA is, regrettably, not making a pivot towards public transportation anytime in the near future. So, lighter cars are one way to address this issue. You didn't expound upon your point about the unintended consequences of CAFE standards but they're very real. Instead of making smaller and more efficient sedans per the guidelines, car makers opted start making all of their vehicles "light trucks" -- 80%+ of new vehicles are SUVs or bubbly looking "crossovers" -- which are not subject to the same demanding standards. Small sedans also cost less and would require ongoing R&D to continue to meet the CAFE standards. The end result, as this thread is interested, is heavier vehicles with bigger tires and more plastic in the environment and our brains.
- linotype 2y ago
  Los Angeles would be very difficult to transition at this point, it’s just too low density. It was better 100 years ago than it is now.
  - lenerdenator 2y ago
    Or Kansas City. Or St. Louis. Or Detroit. Or Chicago, even. Pretty much any major American city is less dense than it was 100 years ago. It was cheaper to build out than it was to build up.
    - wongarsu 2y ago
      From an infrastructure perspective building out instead of up is incredibly expensive. Not just transport but also water, sewage, electricity and internet.
      - lenerdenator 2y ago
        I should specify: it's more expensive for the developers and their home-buying customers to build up instead of out. All of that stuff you listed comes from tax dollars, and people ultimately care less about that than what's coming out of their pockets for a home purchase. Well, until it's unsustainable, anyways.
penjelly 2y ago
EV/hybrid only "zones" in Europe are crazy to me because the electric cars leech more tire carbon into the air anyway. Some regulation seems intelligent on the surface, but the devil is in the details.
- hatthew 2y ago
  Solid/particulate pollution from tires is definitely a problem, but in terms of carbon specifically isn't it many orders of magnitude less than the carbon from gas engines or electric power plants?
  - penjelly 2y ago
    > These particles can include synthetic rubber, plastics, carbon black, and trace metals (like zinc) you're correct. I mistakenly thought it was only carbon coming off the tires. So yeah, EVs have a significantly lower carbon output that ICE vehicles. My point still stands but thanks for the callout.
- dashundchen 2y ago
  EV/hybrids also have regenerative brakes so emit less brake dust. Between emissions, tires, and brakes I'd be curious to see how it balances out. But really cycling and transit are the way to go to make cities more liveable. Personal cars take too much space in a city and ruin the built environment for everyone not in one.
- DoingIsLearning 2y ago
  Excessive NO2 emissions spewed by diesel engines not meeting regulations very literally removed years from our collective life spans in city centres across the world. Despite their own health hazards no amount of tire particulate from EV's can achieve that level of widespread public health impact.
- audunw 2y ago
  These zones are generally densely populated areas, and in Europe they usually have low speed limits, and roads design to encourage driving at low speeds. To think that the minuscule difference in tire dust is significant at all, compared to the pollutants that EVs completely eliminates, is absolutely ridiculous. The devil is in the details, yes. Have you considered that the policy makers have actually looked into the details? Have you looked into the details? Have you read any detailed reports about tire wear or did you just make up a problem based on your own intuition? Because I’ve seen reports from EV fleet operators that indicate that they see no difference in tire wear. Most likely the added weight (which isn’t all that much for modern, smaller EVs.. you know, the ones that people actually drive in urban/suburban areas in Europe) as a factor is drowned by other larger factors. And we’re not that far away from EVs with the same or lower weight than their ICE counterparts, so getting these kinds of policies in place has some forward-looking aspects to them as well.
joseangel_sc 2y ago
I don't think this is entirely true but we need more research https://youtu.be/FcnuaM-xdHw?si=6bvFQdUjHi28CugV https://youtu.be/FcnuaM-xdHw?si=6bvFQdUjHi28CugV
repiret 2y ago
Do you have a citation for the vehicle weight to the fourth figure? There is about a 2X variation in the weight of the vehicles I’ve owned, but even accounting for differences in tire size, I can’t come up with a 16x difference in how often I change the tires. Thinking about it a different way, there isn’t much difference in recommended tire pressure among the autos I’ve owned. That means that the pressure between the road and the tire is relatively constant but the surface area of contact is directly proportional to vehicle weight. For a fixed contact pressure, I am struggling to imagine a physical process by which the rubber loss is not proportional to the contact area.
- darkmighty 2y ago
  I know this figure comes from road wear. I don't know if it applies to tire wear, and indeed I suspect it doesn't, if only because tires tend to scale with vehicle weight as you mentioned. I think road wear may be associated with structural cracking of the road which may not change significantly with tire area.
- deleted 2y ago
  [deleted]
- daemonologist 2y ago
  The fourth power law is usually applied to deformation of asphalt roadways (here's a citation for that: https://www.researchgate.net/profile/Maxwell-Lay/publication/279479007_AIR_000-248/links/559398ba08ae16f493ee7145/AIR-000-248.pdf?origin=publication_list https://www.researchgate.net/profile/Maxwell-Lay/publication...); I haven't heard it applied to tires before. If I had to guess I'd agree with you - I would expect a smaller exponent, particularly if the tires are designed for the given load.
- foonspeeder 2y ago
  [dead]
- kirubakaran 2y ago
  https://en.wikipedia.org/wiki/Fourth_power_law https://en.wikipedia.org/wiki/Fourth_power_law
twelvechairs 2y ago
Roads and road standards are a tragedy of the commons. People keep buying bigger cars and demanding more, wider lanes and parking spaces because they don't take any of the burden individually - it's the taxpayers as a whole that foot the bill. Paradoxically most of the 'small government' types are often the biggest road users.
- sooheon 2y ago
  The solution to tragedies of the commons is to internalize externalities. Tax should scale with carbon use, congestion contribution, and microplastic emission.
- robertlagrant 2y ago
  > Paradoxically most of the 'small government' types are often the biggest road users. I think it's "limited government". I'm pretty sure they would prefer roads get more spending.
guelo 2y ago
None of these things are going to happen. Voters keep voting with their votes and their wallets that they want bigger cars and don't care about climate change. Meanwhile reactionary billionaires have hijacked most of our mass media as we blow by the 1.5°C Paris agreement and Trump dismantles our science institutions.
Lanolderen 2y ago
Also motorcycles/scooters. Unless you have children or live in a place with serious snow a motorcycle and a car sharing app/rentals for when you need to haul a sofa or something is a great combo. Cheap, easy maintenance, good fuel economy and speed, traffic jam immunity..

And we need more lightweight cars , not heavier, since tire wear is proportional to vehicle weight to the fourth power. Ironically, CAFE regulations and EV incentives both did the opposite

kijin 2y ago

> tire wear is proportional to vehicle weight to the fourth power. Does this mean that a bus that weighs 10 times as much as a small car will produce 10000 times as much tire dust? If it does, I'm not sure if investing in buses will reduce tire dust at all. A bus can replace a lot of cars, but 10000 is a stretch. We need more trains.

deleted 2y ago
[deleted]
penjelly 2y ago
trams were popular in tons of places before, I understand they improved traffic significantly compared even to today, and they'd still have a positive effect now, I think. But most places shifted towards a car centric focus and we lost those.
zamadatix 2y ago
I think the root observation here comes from https://en.wikipedia.org/wiki/Fourth_power_law https://en.wikipedia.org/wiki/Fourth_power_law which really talks about the inferred stress to the road for given weight on the axle, not tire wear based on vehicle weight. The above seems to be using a simplification based on passenger cars staying with 4 tires across 2 axles but how this relates to tire wear is going to be a bit more complicated when you start talking about vehicles which can have more axles, more tires per axle, and significantly larger tires. I'd believe buses have a lot of tire wear compared to an individual car but I wouldn't use that relation as proof of just how many times so.

ethagnawl 2y ago

I'm not sure why you're being down voted for suggesting a practical and fact based solution. The USA is, regrettably, not making a pivot towards public transportation anytime in the near future. So, lighter cars are one way to address this issue. You didn't expound upon your point about the unintended consequences of CAFE standards but they're very real. Instead of making smaller and more efficient sedans per the guidelines, car makers opted start making all of their vehicles "light trucks" -- 80%+ of new vehicles are SUVs or bubbly looking "crossovers" -- which are not subject to the same demanding standards. Small sedans also cost less and would require ongoing R&D to continue to meet the CAFE standards. The end result, as this thread is interested, is heavier vehicles with bigger tires and more plastic in the environment and our brains.

linotype 2y ago
Los Angeles would be very difficult to transition at this point, it’s just too low density. It was better 100 years ago than it is now.
- lenerdenator 2y ago
  Or Kansas City. Or St. Louis. Or Detroit. Or Chicago, even. Pretty much any major American city is less dense than it was 100 years ago. It was cheaper to build out than it was to build up.
  - wongarsu 2y ago
    From an infrastructure perspective building out instead of up is incredibly expensive. Not just transport but also water, sewage, electricity and internet.
    - lenerdenator 2y ago
      I should specify: it's more expensive for the developers and their home-buying customers to build up instead of out. All of that stuff you listed comes from tax dollars, and people ultimately care less about that than what's coming out of their pockets for a home purchase. Well, until it's unsustainable, anyways.

penjelly 2y ago

EV/hybrid only "zones" in Europe are crazy to me because the electric cars leech more tire carbon into the air anyway. Some regulation seems intelligent on the surface, but the devil is in the details.

hatthew 2y ago
Solid/particulate pollution from tires is definitely a problem, but in terms of carbon specifically isn't it many orders of magnitude less than the carbon from gas engines or electric power plants?
- penjelly 2y ago
  > These particles can include synthetic rubber, plastics, carbon black, and trace metals (like zinc) you're correct. I mistakenly thought it was only carbon coming off the tires. So yeah, EVs have a significantly lower carbon output that ICE vehicles. My point still stands but thanks for the callout.
dashundchen 2y ago
EV/hybrids also have regenerative brakes so emit less brake dust. Between emissions, tires, and brakes I'd be curious to see how it balances out. But really cycling and transit are the way to go to make cities more liveable. Personal cars take too much space in a city and ruin the built environment for everyone not in one.
DoingIsLearning 2y ago
Excessive NO2 emissions spewed by diesel engines not meeting regulations very literally removed years from our collective life spans in city centres across the world. Despite their own health hazards no amount of tire particulate from EV's can achieve that level of widespread public health impact.
audunw 2y ago
These zones are generally densely populated areas, and in Europe they usually have low speed limits, and roads design to encourage driving at low speeds. To think that the minuscule difference in tire dust is significant at all, compared to the pollutants that EVs completely eliminates, is absolutely ridiculous. The devil is in the details, yes. Have you considered that the policy makers have actually looked into the details? Have you looked into the details? Have you read any detailed reports about tire wear or did you just make up a problem based on your own intuition? Because I’ve seen reports from EV fleet operators that indicate that they see no difference in tire wear. Most likely the added weight (which isn’t all that much for modern, smaller EVs.. you know, the ones that people actually drive in urban/suburban areas in Europe) as a factor is drowned by other larger factors. And we’re not that far away from EVs with the same or lower weight than their ICE counterparts, so getting these kinds of policies in place has some forward-looking aspects to them as well.

joseangel_sc 2y ago

I don't think this is entirely true but we need more research https://youtu.be/FcnuaM-xdHw?si=6bvFQdUjHi28CugV https://youtu.be/FcnuaM-xdHw?si=6bvFQdUjHi28CugV

repiret 2y ago

Do you have a citation for the vehicle weight to the fourth figure? There is about a 2X variation in the weight of the vehicles I’ve owned, but even accounting for differences in tire size, I can’t come up with a 16x difference in how often I change the tires. Thinking about it a different way, there isn’t much difference in recommended tire pressure among the autos I’ve owned. That means that the pressure between the road and the tire is relatively constant but the surface area of contact is directly proportional to vehicle weight. For a fixed contact pressure, I am struggling to imagine a physical process by which the rubber loss is not proportional to the contact area.

darkmighty 2y ago
I know this figure comes from road wear. I don't know if it applies to tire wear, and indeed I suspect it doesn't, if only because tires tend to scale with vehicle weight as you mentioned. I think road wear may be associated with structural cracking of the road which may not change significantly with tire area.
deleted 2y ago
[deleted]
daemonologist 2y ago
The fourth power law is usually applied to deformation of asphalt roadways (here's a citation for that: https://www.researchgate.net/profile/Maxwell-Lay/publication/279479007_AIR_000-248/links/559398ba08ae16f493ee7145/AIR-000-248.pdf?origin=publication_list https://www.researchgate.net/profile/Maxwell-Lay/publication...); I haven't heard it applied to tires before. If I had to guess I'd agree with you - I would expect a smaller exponent, particularly if the tires are designed for the given load.
foonspeeder 2y ago
[dead]
kirubakaran 2y ago
https://en.wikipedia.org/wiki/Fourth_power_law https://en.wikipedia.org/wiki/Fourth_power_law

twelvechairs 2y ago

Roads and road standards are a tragedy of the commons. People keep buying bigger cars and demanding more, wider lanes and parking spaces because they don't take any of the burden individually - it's the taxpayers as a whole that foot the bill. Paradoxically most of the 'small government' types are often the biggest road users.

sooheon 2y ago
The solution to tragedies of the commons is to internalize externalities. Tax should scale with carbon use, congestion contribution, and microplastic emission.
robertlagrant 2y ago
> Paradoxically most of the 'small government' types are often the biggest road users. I think it's "limited government". I'm pretty sure they would prefer roads get more spending.

guelo 2y ago

None of these things are going to happen. Voters keep voting with their votes and their wallets that they want bigger cars and don't care about climate change. Meanwhile reactionary billionaires have hijacked most of our mass media as we blow by the 1.5°C Paris agreement and Trump dismantles our science institutions.

Lanolderen 2y ago

Also motorcycles/scooters. Unless you have children or live in a place with serious snow a motorcycle and a car sharing app/rentals for when you need to haul a sofa or something is a great combo. Cheap, easy maintenance, good fuel economy and speed, traffic jam immunity..