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At a hefty 3.5T / 7,000 lbs, the Rivians* aren't much lighter than an E-Hummer (4.5T / 9,000 lbs). Isn't road wear non-linear, with heavy vehicles doing dispro

At a hefty 3.5T / 7,000 lbs, the Rivians* aren't much lighter than an E-Hummer (4.5T / 9,000 lbs). Isn't road wear non-linear, with heavy vehicles doing disproportionate damage compared to lighter ones? Ever noticed how the trucker lanes on the highway are the first to get potholes? The taxpayers shouldn't be forced to subsidize luxury toys. Let the owners pay a fair amount relative to the strain they're adding to the system (and FWIW, I'm saying this as someone who's immediate family members [plural] own Rivians). * I was surprised to learn the gross weight of a Rivian the other night at dinner while peeking at a relative's car registration documents on the kitchen counter :p

whartung 3y ago
How much damage does a 7,000 lb vehicle do to a road designed for 80,000 lb? Or is the real measure ground pressure? Apparently semi trucks run 6000lb up front per wheel and 4300lb in the rear. The Rivian runs 1400lb. With asphalt, which is softer, I imagine the road damage more readily accumulates over time. Whereas the concrete on freeways I guess has an actual sheer strength and either breaks or it doesn’t. I am neither a mechanical nor civil engineer, so just curious how the wear manifests.
- psunavy03 3y ago
  I don't think this thread is as much about actual tire wear as it is a bunch of people preening about how Trucks Bad because You Don't Need That.
  - hanszarkov 3y ago
    This.
margalabargala 3y ago
> Isn't road wear non-linear, with heavy vehicles doing disproportionate damage compared to lighter ones? This is correct, and it's why your conclusion is nonsensical. No one is subsidizing luxury toys. The amount of damage done to roads by an e-Hummer or Rivian is mildly above that of, say, a Camry. Both do hundreds of times less damage than an 18-wheeler. The amount of damage done to a road by a passenger sedan is functionally zero, and for a Rivian or Hummer, it remains essentially zero. The weight of large electric vehicles is an important issue! It makes a huge difference in cases of, for example, striking a pedestrian. But road damage is not a major issue for electric vehicles. One caveat would be that a lot of road repair is funded via gas taxes, so road damage per dollar paid towards road repair may be lower for electric vehicles. But if we make heavy vehicles pair "their fair share", the Rivians will pay pennies, and the truckers will all go bankrupt.
- deleted 3y ago
  [deleted]
- dcan 3y ago
  > the truckers will all go bankrupt I still think the alternative to pay per weight*distance is good - trucks should be last-mile delivery, not the primary source of transportation for goods in North America. Cargo trains are much better in many different dimensions, even more-so if they're electrified (Though, that's an impossibility in this market)
  - psunavy03 3y ago
    Tell me you've never worked in logistics without telling me you've never worked in logistics.
    - wolfgang42 3y ago
      We put a lot of effort into not using rail for freight, it stands to reason that if we actually set our minds to it we could start using it more again. (At least, I think that the argument you’re making is about modern logistics and modern rail freight being surprisingly incompatible. But it’s hard to tell since you haven’t actually provided a rebuttal.)
    - c0nducktr 3y ago
      For all of us who haven't worked in logistics, why not explain what you're talking about instead of being snarky?
      - psunavy03 3y ago
        I work for a logistics company which operates a hub-and-spoke network of trucks running between its branches in the US and Europe. Think just like an airline running scheduled flights, but with trucks going warehouse to warehouse. The truck is contracted out to a service provider, and goes on schedule regardless of what is on it at the time. The reason we do this is because it offers a predictable way of getting stuff from point A to point B using existing infrastructure. And 99 times out of 100, with the volumes we move, the truck is full of something. Or many somethings. And when you move the volumes of freight we do, that helps us fulfill our business case, which is "give us your stuff. Here's the paperwork saying we take responsibility. We'll make sure it arrives at point B on time, compliant with customs and all import/export laws, and compliant with all your industry's off-the-wall niche requirements, without you having to do so much as think about it anymore." This isn't feasible using only rail without multiple governments across the world investing billions or maybe trillions of dollars/Euros in new track. Especially in America, where the rail network has always gotten outcompeted by truck freight for many different reasons. What you're describing is a pie-in-the-sky ideal, not what's necessarily feasible without making freight prices skyrocket due to high rail demand, low capacity, and the probably 25+ years it would take to change this. If not 50-100 years.
judge2020 3y ago
I mentioned this in my comment, but the "AASHO Road Test" gave us something called the Generalized Fourth Power Law. Explained > It’s a rule of thumb for comparing the amount of pavement damage caused by vehicles with different weights, in terms of axle loads: > (W1/W2)^4 > In the equation, W1 is the weight of an axle on vehicle 1, which we would compare to W2, the weight of an axle on vehicle 2. For W1 of 4 tons on an axle and W2 of 1 ton on an axle, vehicle 1 does 256 times as much damage to pavement as vehicle 2.
- TacticalCoder 3y ago
  > For W1 of 4 tons on an axle and W2 of 1 ton on an axle, vehicle 1 does 256 times as much damage to pavement as vehicle 2. OK so take a loaded semi-truck at 40 tons / 80 000 pounds. How much more damage does it do than the 4 tons W1 of your example? How's the road still even there at all after the semi-truck passed on it? The answer is: because even the W1 vehicle at 4 tons cannot even dent that road. Now I'm not saying a 4 tons car is a good thing but honestly 1 ton to 2.5 tons, I don't think it's even possible to measure the tiny damage they do.
  - judge2020 3y ago
    Indeed. So while a 4.5 ton vehicle, the Hummer EV, does 25 times as much damage as a 2 ton sedan, a semi truck with 5 tons on each axle does ~625 times as much damage to the road. But 5 tons is not the standard. The federal axel limit is 20,000 pounds, so a fully loaded truck could be doing the same amount of damage to the road as 10,000 sedans. I doubt this is the average axle weight of all semis on the road, though.
  - Timshel 3y ago
    You do realize that not all roads are designed to allow for frequent 40t trucks usage (and they should not). So they might not dent a highway but probably not the same for city streets / suburbs and parkings.
- coredog64 3y ago
  The AASHO test comes up frequently, but there’s an easier way to evaluate this: What’s the internal pressure required to inflate the tires? The higher it is, the smaller the contact patch and the more damage it will inflict on the road. Large trucks are between 80 and 100 PSI, while your typical passenger vehicle is going to be 35 PSI or under.
deleted 3y ago
[deleted]

whartung 3y ago

How much damage does a 7,000 lb vehicle do to a road designed for 80,000 lb? Or is the real measure ground pressure? Apparently semi trucks run 6000lb up front per wheel and 4300lb in the rear. The Rivian runs 1400lb. With asphalt, which is softer, I imagine the road damage more readily accumulates over time. Whereas the concrete on freeways I guess has an actual sheer strength and either breaks or it doesn’t. I am neither a mechanical nor civil engineer, so just curious how the wear manifests.

psunavy03 3y ago
I don't think this thread is as much about actual tire wear as it is a bunch of people preening about how Trucks Bad because You Don't Need That.
- hanszarkov 3y ago
  This.

margalabargala 3y ago

> Isn't road wear non-linear, with heavy vehicles doing disproportionate damage compared to lighter ones? This is correct, and it's why your conclusion is nonsensical. No one is subsidizing luxury toys. The amount of damage done to roads by an e-Hummer or Rivian is mildly above that of, say, a Camry. Both do hundreds of times less damage than an 18-wheeler. The amount of damage done to a road by a passenger sedan is functionally zero, and for a Rivian or Hummer, it remains essentially zero. The weight of large electric vehicles is an important issue! It makes a huge difference in cases of, for example, striking a pedestrian. But road damage is not a major issue for electric vehicles. One caveat would be that a lot of road repair is funded via gas taxes, so road damage per dollar paid towards road repair may be lower for electric vehicles. But if we make heavy vehicles pair "their fair share", the Rivians will pay pennies, and the truckers will all go bankrupt.

deleted 3y ago
[deleted]
dcan 3y ago
> the truckers will all go bankrupt I still think the alternative to pay per weight*distance is good - trucks should be last-mile delivery, not the primary source of transportation for goods in North America. Cargo trains are much better in many different dimensions, even more-so if they're electrified (Though, that's an impossibility in this market)
- psunavy03 3y ago
  Tell me you've never worked in logistics without telling me you've never worked in logistics.
  - wolfgang42 3y ago
    We put a lot of effort into not using rail for freight, it stands to reason that if we actually set our minds to it we could start using it more again. (At least, I think that the argument you’re making is about modern logistics and modern rail freight being surprisingly incompatible. But it’s hard to tell since you haven’t actually provided a rebuttal.)
  - c0nducktr 3y ago
    For all of us who haven't worked in logistics, why not explain what you're talking about instead of being snarky?
    - psunavy03 3y ago
      I work for a logistics company which operates a hub-and-spoke network of trucks running between its branches in the US and Europe. Think just like an airline running scheduled flights, but with trucks going warehouse to warehouse. The truck is contracted out to a service provider, and goes on schedule regardless of what is on it at the time. The reason we do this is because it offers a predictable way of getting stuff from point A to point B using existing infrastructure. And 99 times out of 100, with the volumes we move, the truck is full of something. Or many somethings. And when you move the volumes of freight we do, that helps us fulfill our business case, which is "give us your stuff. Here's the paperwork saying we take responsibility. We'll make sure it arrives at point B on time, compliant with customs and all import/export laws, and compliant with all your industry's off-the-wall niche requirements, without you having to do so much as think about it anymore." This isn't feasible using only rail without multiple governments across the world investing billions or maybe trillions of dollars/Euros in new track. Especially in America, where the rail network has always gotten outcompeted by truck freight for many different reasons. What you're describing is a pie-in-the-sky ideal, not what's necessarily feasible without making freight prices skyrocket due to high rail demand, low capacity, and the probably 25+ years it would take to change this. If not 50-100 years.

judge2020 3y ago

I mentioned this in my comment, but the "AASHO Road Test" gave us something called the Generalized Fourth Power Law. Explained > It’s a rule of thumb for comparing the amount of pavement damage caused by vehicles with different weights, in terms of axle loads: > (W1/W2)^4 > In the equation, W1 is the weight of an axle on vehicle 1, which we would compare to W2, the weight of an axle on vehicle 2. For W1 of 4 tons on an axle and W2 of 1 ton on an axle, vehicle 1 does 256 times as much damage to pavement as vehicle 2.

TacticalCoder 3y ago
> For W1 of 4 tons on an axle and W2 of 1 ton on an axle, vehicle 1 does 256 times as much damage to pavement as vehicle 2. OK so take a loaded semi-truck at 40 tons / 80 000 pounds. How much more damage does it do than the 4 tons W1 of your example? How's the road still even there at all after the semi-truck passed on it? The answer is: because even the W1 vehicle at 4 tons cannot even dent that road. Now I'm not saying a 4 tons car is a good thing but honestly 1 ton to 2.5 tons, I don't think it's even possible to measure the tiny damage they do.
- judge2020 3y ago
  Indeed. So while a 4.5 ton vehicle, the Hummer EV, does 25 times as much damage as a 2 ton sedan, a semi truck with 5 tons on each axle does ~625 times as much damage to the road. But 5 tons is not the standard. The federal axel limit is 20,000 pounds, so a fully loaded truck could be doing the same amount of damage to the road as 10,000 sedans. I doubt this is the average axle weight of all semis on the road, though.
- Timshel 3y ago
  You do realize that not all roads are designed to allow for frequent 40t trucks usage (and they should not). So they might not dent a highway but probably not the same for city streets / suburbs and parkings.
coredog64 3y ago
The AASHO test comes up frequently, but there’s an easier way to evaluate this: What’s the internal pressure required to inflate the tires? The higher it is, the smaller the contact patch and the more damage it will inflict on the road. Large trucks are between 80 and 100 PSI, while your typical passenger vehicle is going to be 35 PSI or under.

deleted 3y ago

[deleted]