12 ms·
Maybe offtopic but a surprising bit of extra information regarding wear and vehicles: Road wear scales with the fourth power of axle load, so heavier vehicles
by _Microft 7y ago
Maybe offtopic but a surprising bit of extra information regarding wear and vehicles:
Road wear scales with the fourth power of axle load, so heavier vehicles do much more damage than one might expect.
Take a 40t truck with 5 axles vs. a small car with a weight of 1t and two axles (e.g. VW Polo, maybe an older VW Golf might only weigh 1t as well):
(8t axle load / 0.5t axle load) = 16^4, i.e. the truck puts 2^16 (65536) times as much wear on the street as the car.
(8t axle load / 1t axle load (SUV)) = 8^4 = 2^12, even comparing it with an SUV and an axle load of 1t each, the truck is still 4096 times worse.
https://en.wikipedia.org/wiki/Road#Maintenance https://en.wikipedia.org/wiki/Road#Maintenance
https://books.google.de/books?id=7Yqxyefv-VAC&pg=PA252&dq=4th+power+of+axle+weight&redir_esc=y&hl=de#v=onepage&q=4th%20power%20of%20axle%20weight&f=false https://books.google.de/books?id=7Yqxyefv-VAC&pg=PA252&dq=4t...
- abyssin 7y agoI remember a hitchhiking ride in France with a man working in the building and infrastructure industry telling me about these figures, and the intense lobbying against transporting goods on rails...
- dukoid 7y agoIn France the rubber tyre lobby is so strong, the got them on subway cars. No joke: https://en.wikipedia.org/wiki/Rubber-tyred_metro https://en.wikipedia.org/wiki/Rubber-tyred_metro
- forkexec 7y agoAt Michelin, we're more than just Green guides, we put our tires on the subway cars and encourage protesters to use ours for all their tire fire needs.
- tomohawk 7y agoMaybe the study should also take into account this use of tyres.
- pyrale 7y agoThe subway has tires for technical reasons. Stations in the Paris subway are close enough that better acceleration times have a significant impact on travel time and peak-hour capacity.
- derefr 7y agoIf they were willing to retool, you’d think they’d just go with a maglev monorail design. Those have the capacity for the instantaneous acceleration of a railgun.
- DFHippie 7y agoThat would be a pretty rough ride. I wouldn't want to be a straphanger on one of those. The turns would be uncomfortable as well in a railgun railway car.
- roywiggins 7y agoIt would also be useless, the stations are so dense that you would barely increase the average speed.
- derefr 7y agoI didn’t mean to suggest you’d use it as a railgun. It just has the capacity for exactly as much torque as you need from it at any given moment.
- Sam777666 7y agoIn January there was this report: Microscopic pieces of plastic have been discovered in the most remote locations, from the depths of the ocean to Arctic ice. Another place that plastic is appearing is inside our bodies. We’re breathing microplastic, eating it and drinking plastic-infused water every day.Plastic does not biodegrade. Instead, it breaks down into smaller pieces, and ultimately ends up everywhere, including in the food chain. Pieces that are less than five millimeters in length, around the size of a sesame seed, are called “microplastics.” https://graphics.reuters.com/ENVIRONMENT-PLASTIC/0100B4TF2MQ/index.html?utm_source=twitter&utm_medium=Social https://graphics.reuters.com/ENVIRONMENT-PLASTIC/0100B4TF2MQ...
- hef19898 7y agoOn Germany the best lobby work to put transportation on truck instead of rail is done by DB, German Railroads, with their freight services. Compared to trucking you can easily double lead times, increase costs per ton and decrease trackability and reliability.
- kungtotte 7y agoSame thing in Sweden. Lower costs for the customers and higher reliability when you ship by truck means rail is not really a consideration even though it would be better for everyone if it actually worked.
- pinko 7y agoI remember a civil engineer telling me once that if highways only had cars on them they would last 100 years between repavings.
- zip1234 7y agoI highly doubt this in cold areas but might be true elsewhere
- CydeWeys 7y agoPlow trucks aren't cars.
- seattle_spring 7y agoPretty sure GP is referring to the damage caused by the freeze/thaw cycle.
- gbear605 7y agoThe problem isn’t the plow trucks, but the expanding and contracting water causes cracks. Roads that never get trucks on them get potholes
- Spooky23 7y agoMy dads driveway in upstate NY was paved in the 90s and is pretty pristine, but it’s surfaced every 2 years and well drained.
- tyfon 7y agoI don't doubt it, we have a local road here that has been fine, but this year they decided to drive a lot of truck loads of snow to save a skiing event from another city up that road and now it's completely destroyed and it needs new pavement and possibly new foundations in several places. Trucks should really only be a last resort for the last mile to the store and the rest should be sent by rail or boat and loaded onto trucks if necessary. They also have huge externalities when it comes to damage to other cars, when my car is hit by rocks on the road it is always coming from a truck.
- seattle_spring 7y agoThis fact is especially pertinent when folks with their F150s demand that road bikes be taxed equally to use bike lanes.
- iso947 7y agoTaxing by fourth power axel weight per mile sounds good $10 for a bike doing 1000 miles a year, so 1 cent a mile. Gross axel weight about 100lb. So axel weight of 1000lb would be $100 a mile. F150 at 2500lb would be $4,000 a mile. I suggest putting the first year on the sale price, so that $200 bike costs $210, and the $60k f150 costs $60 million.
- seattle_spring 7y agoYep that's usually the response I give to folks in my neighborhood FB group. They are conspicuously absent to the conversation after that.
- read_if_gay_ 7y agoWell maybe because it's a total nonsense argument? Unless you actually want to kill all road transport and everything reliant on it, which is effectively everything, in which case I also think it's clear why you're not getting any replies.
- SilasX 7y agoPer my other comment [1], it’s nonsense to actually collect $4000, but it’s not nonsense to have the ratios work like that. Such a tax would eliminate marginal uses of trucks but not eliminate trucks entirely (since it would be a higher but not ridiculous tax). It also works as a reductio against any wear-based tax on bikes, since it would imply an absurd tax on trucks. [1] https://news.ycombinator.com/item?id=22519021 https://news.ycombinator.com/item?id=22519021 (Edited over past hour to fix numerous typos.)
- 7y ago
- a3n 7y ago> Take a 40t truck with 5 axles vs. a small car with a weight of 1t and two axles ... Truck driver. Not quibbling, just adding nuance. For your typical 40t scenario, allowed max weights are: 12,00 pounds on the front steering axle. It has one tire at each end. 34,000 pounds total on the two tandem "drive" axles on the truck. There are two tires at the end of each axle, so four per axle, eight total at the drive axles, and ten total on the truck. 34,000 pounds on the two tandem axles on the trailer, two tires at the end of each axle, eight total on the trailer axles, 18 total on the truck plus trailer rig. 34K + 34K + 12K = 80,000 pounds = 40t, if the trailer is fully loaded to max. It's about 35,000 pounds total if the trailer is empty. So you should include in your calculations that the load is spread out over eighteen tires, as above. There is also bridge loading to consider. https://en.wikipedia.org/wiki/Federal_Bridge_Gross_Weight_Formula https://en.wikipedia.org/wiki/Federal_Bridge_Gross_Weight_Fo...
- dhimes 7y agoSo it would be better to have a bunch of smaller trucks moving cargo. And that means a lot more work for truck drivers.
- a3n 7y agoLots of ways to cut that. Consider pounds-mile/gal for freight on my 80k truck carrying 45k freight, vs your vanagon or beemer. My truck gets at least 6mpg, usually 7.5, sometimes 9, and I've seen 10 once.
- richk449 7y agoTrue, reducing the cargo would require more trucks to carry the same load, increasing demand for truck drivers. On the other hand, wouldn’t reducing the amount of cargo a single truck can carry makey individual truck driver less valuable? The end result would probably depend on a lot of other factors, including the supply and demand curves for alternative forms of transportation (trains, boats, investment in autonomous solutions), as well as the supply and demand curves of the goods being transported (because if the cost goes up to pay for more truck drivers, maybe people will just stop buying that product).
- 7y ago
- amelius 7y ago> Road wear scales with the fourth power of axle load, so heavier vehicles do much more damage than one might expect. Yes. Electric vehicles with their heavy batteries also make things worse.
- ghouse 7y agoExcept no. The heaviest Tesla Model 3 weighs 4,100 lbs. The heaviest Ford F-150 (the most popular vehicle in the US) weighs 5,600 lbs.
- nightski 7y agoRight but people buying F-150s are not buying Teslas. The use case is quite different. My Subaru Outback (a rather large car in comparison to the Tesla) is 3,600 lbs. But I doubt the increase in weight is a huge factor in environmental concerns.
- ghouse 7y agoBut compared to freight trucks, the F-150, the EV, and the Outback are all inconsequential.
- rcpt 7y ago> The use case is quite different. If you want to make this argument you should account for the weight of a loaded F150
- lkbm 7y ago> Right but people buying F-150s are not buying Teslas. The use case is quite different. Have you been to a Texas city? They're full of F-150s driving around a single person and an empty bed on paved roads. Sure, farmers and contractors use trucks as trucks, but thousands of people use them as commuter cars. Most pickup trucks are used as trucks once in a blue moon.
- deleted 7y ago[deleted]
- tomohawk 7y agoA family member was a civil engineer in the Federal Highway Administration for many decades, specifically in concrete pavement design, and remained an a technical career path the whole time. He had many war stories to tell related to the trucking industry. In one, they had developed a scale that could measure the weight per axle of vehicles on the roadway without requiring the vehicles to slow down. They wanted to embed these in a few places to prove how bad things really were with overloaded trucks. The trucking industry bought off some congress critters who would only allow them to put the scale at one clearly marked location on an interstate, in one lane. The lane next to the scale lane was crushed by all the trucks driving in that lane to avoid the scale.
- logicallee 7y ago>Road wear scales with the fourth power of axle load Could you explain why? (I can't view the Google books link.)
- masklinn 7y agoThere's no "why", it's a rule of thumb / estimate called the "fourth power rule" (or "fourth power law" but there are other unrelated fourth power laws) established experimentally in the late 50s / early 60s by the AASHO. Basically they built a bunch of roads to the same specifications, drove streams of vehicles through and monitored pavement deterioration.
- londons_explore 7y agoI'd be interested to know how wear scales with tyre pressure. The tyre pressure exactly matches the pressure on one spot on the road surface, so if pressure is higher, a smaller area of the road receives more downward force, causing it to bend and flex, and eventually break up.
- masklinn 7y ago> I'd be interested to know how wear scales with tyre pressure. Apparently not in any way relevance in face of the fourth power rule, as road authorities worldwide just use the 4th power rule for road wear estimates, without accounting for minor factors (type of axles, axle arrangement, surface contact and suspension systems).
- chiefalchemist 7y agoI'll take your off-topic a step further ;) A couple days ago on one of the NPR shows they interviewed a long-haul truck driver. At one point he said (paraphrasing), "If you bought physical goods, it was transported by truck." Given the amount of consumption (of physical goods) that's a significant amount of tire wear.
- kungtotte 7y agoHe was underselling it. Unless you walked naked out into the woods and built your life entirely from found materials, literally everything in your life was at some point or another hauled by a truck. Everything. This is not a hyperbolic way to make an argument, it's the truth. Sometimes you'll have to go pretty far back the chain of events, maybe as far as raw materials, but at some point (probably several) X was on a truck for any X. A hippie commune that grow all their own food living off the grid? Their clothes, their tools, the paint on their house, it all rode on trucks. Two-ish years ago truckers in Brazil went on a strike to protest increased gas prices and corruption and it only took three days before the president ordered the military to force the trucks into moving again. That's how hard it hits if trucks stop moving. The military couldn't do shit though because the trucks hauling the diesel powering the military vehicles were part of the protest so they got nowhere. If all the trucks stop right this second, we'll be living in post-apocalyptic chaos by Friday. No joke.
- hinkley 7y agoDo you think that has any bearing on the triple trailer situation that seems to be developing?
- masklinn 7y agoDepends how the axle load changes.
- globular-toast 7y agoI drive on one of the routes used by lorries servicing the UK's largest container port. The roads are visibly buckled in the lanes the lorries use. You can feel your car uncomfortably slotting into the grooves. It seems insane to me to use the roads for that. A railway seems like a complete no brainer, especially considering these are containers and easily loaded. But at least the weight of a lorry consists of mostly the goods being transported. The more pertinent comparison is a bicycle vs single-occupant "SUV". Unlike lorries, those things are tearing up smaller roads in town centres making the roads barely usable by smaller cars, let alone bicycles, despite the fact that cyclists contribute equally to road maintenance. Those SUVs also require larger brakes which is a major non-exhaust emission. It's high time to start taxing these vehicles heavily and I think using the fourth power of axle load seems like a sensible way to do it.
- hirundo 7y agoLike hiking trails. It takes a large number of people on boots to do the damage of one person on a horse on horseshoes.
- gok 7y agoSuggests we should ban buses.