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Comment by dougweltman | Hacker News Reader

This does not address a larger question: how much does a mile of road cost to keep? This is the installed base question.

Consider the amount of road that has been built out in the US relative to the populations that road is serving. Maintenance and expansion is paid out mainly from state and local taxes. That's an enormous civilizational overhead the US contends with, not to mention the economic cost of a large portion of household capital being tied up in rapidly depreciating assets: cars.

I'm looking at you, suburbia.

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Look all you want, but road maintenance costs are primarily a subsidy for the trucking industry, and by extension the businesses that rely on them. Businesses that are primarily located in.....cities. If Middletown USA didn't have to worry about 80,000 lbs trucks hauling kombucha to your local bodega tearing up their roads, perhaps road costs would be a bit more in-line with reality.

More importantly if we focused more on making transport costs in-line with the damage they do to the road surfaces (not to mention the environmental impact of long and short haul trucking, plus the traffic) instead of city/suburbia none issue, perhaps we'd all be a bit better off.

The proper solution would be to tax trucks exactly the amount of damage they cause. This would cause the cost of imported goods to go up and the cost of local goods to go down. In the short term you would see the extra cost and lower taxes cancel each other out and in the long term, local goods become more common than imported.

Thats certainly one solution, and a perfectly reasonable one at that. It seems to be an excellent way by which we can also encourage more rail development, and reduce the overall amount of waste in the transport chain.

You'll also see trucks use more axles with wider, softer tires. It's easy to get more than an order of magnitude in damage reduction.

This is the right idea, but let's not stop there. Why not also tax privately registered vehicles to some degree by their mass?

I also like the idea of making fines for moving violations somewhat proportional to vehicle mass. The danger posed to others by a 150 lb moped pales in comparison to that of a 4500 lb pickup truck. At least in the U.S., a ticket for speeding 50% over the limit through a residential neighborhood is the same for both, for example. Neither is OK, but considering the disparity in the potential for damage and injury to others, imposing equal fines is insane.

Because "privately registered" vehicles don't matter for purposes of road damage.

A fully loaded semi is 18,000 lbs per axle. A really huge personal vehicle, an F-350, is 4000 lbs per axle. That's 4.5x the weight, 4.5^4=410, so the semi is doing 410x as much damage. There's really no point in trying to tax personal vehicles for road damage when over 99% of the damage is being done by trucks.

Where are you getting your "over 99%" figure?

You need to approach or exceed a roads per-axel weight limit to do any damage or serious wear.

Trucks and permit loads are pretty much the only things that get close.

Beyond the elastic limit, damage is an exponential function of the pavement loading, but only once that certain minimum psf is hit.

For the majority of a highway's loading curve, the damage-per-force is essentially nil. Plastic deformation and serious fatigue only start as you approach the design limits.

It's 99%+ because cars don't do any real wear or damage to pavement from typical use.

A semi is doing 400x as much damage as essentially the heaviest personal vehicle driving. For a more typical car at 4000 lbs (2000 lbs per axle), the semi does 6000x as much damage. If semis are 2% of all traffic (true in my observation), they're doing over 99% of the damage to roads. It makes no sense to care about road damage at all from any vehicle other than a heavy truck.

The GVWR on a F350 is around 10-14,000, so somewhere between 5-7k axle load.

Yes that's the gross weight, i.e. carrying its maximum rated load. Personal vehicles are very rarely loaded up to their maximum weight, and mostly are driven relatively empty.

Even driven at gross weight, it's doing 5% of the damage per axle of loaded semi. The semi also has 4-5 axles, so it's more like 2% of the damage of the semi.

Mind you, we're talking here about the most damaging personal vehicle loaded to its maximum weight, and the semi is still doing 50x the damage of the personal vehicle. It's reasonable to say that essentially all road damage is done by semis.

For the most part I agree. The other issue is psi load produced by different tread patterns. Going from some minimal water channels to a mud terrain cleated style will reduce surface area a good bit. If you have experience with rural areas you don't need a calculator to observe the highest direct damage is usually from agricultural tractors. Deformation from a single pass can be observed (and often felt) with the naked eye in many cases.

Well, after all, the whole point of these tires is to dig into the "road" to get better traction than is possible with normal friction, so it's not too surprising that they dig in to a lesser extent on hard surfaced roads.

That said, this type of tire is a very tiny fraction of the total miles driven on public highways, and so if you're looking for someone to tax based on the costs they create, it's all heavy trucks.

In my state, we're implementing a cost per mile for vehicle registration purposes. I think the idea is tied to air quality concerns, but a similar model would work for road maintenance.

I just wonder what would happen if we charged trucks based on weight.

Which is always easier said than done and a bit simplistic. The primary factor derived to date has been to tie the wear factor to axle weight. Meaning an empty vehicle made for transporting goods would be in the range of passenger vehicles. In addition to simple overloading, improperly balanced loading represents more damage for the same total vehicle weight. So each axle must be weighed in a loaded state on each individual trip to determine the presumptive proportional tax burden.

All of which creates overhead in the form of people to be paid, equipment to build/own/maintain, time lost at all stages, the usual political influence problems, jusrisdiction of different areas of road, implementing policy, and corruption. Most of it will end end up as pass through cost to individuals either way as both consumer goods and roadways are deemed essential. It's ultimately a fairness exercise of tax distribution so like most things in the public interest the arena any idea must be fought in is politics.

Don't we already weigh trucks as they enter and leave the state, as well as sometimes in the middle of the state? I don't know what goes on there already, but we could certainly charge trucks based on loaded miles in the state, which should be pretty easy to calculate since they have very predictable driving patterns and take fairly detailed logs. For local deliveries, we could just charge based on the max load and allow drivers to prove anything otherwise.

And yes, consumers will pay regardless, but at least the difference is reflected in the cost of goods. It could very well be that certain local goods are cheaper than imported goods after road costs are properly factored in, which could change how much is imported.

However, this feels a bit regressive since poorer people will pay more of the cost since roads are largely funded by income tax, but that can be accounted for by shifting other taxes. The idea isn't too punish poor people or shipping customers, but to allow the market to work more efficiently.

Shouldn't roads that are heavily trafficked by trucks by made out of concrete instead of asphalt? Surely it's known that it lasts much longer, I guess the question is if it's economically viable considering long term costs.

For the curious, "Road damage ... is estimated to be proportional to the fourth power of the axle weight". [0] A chart shows it nicely: https://streets.mn/2016/07/07/chart-of-the-day-vehicle-weigh...

[0]: https://en.m.wikipedia.org/wiki/Gross_axle_weight_rating#Imp...

Also, it's an elasticity problem. There is essentially no damage and minimal wear until the forces exceed the elastic limit on the stress-strain curve.

A road is a spring, and will behave elastically, with almost no deformation, unless you exceed a certain point on the stress-strain curve.

This is why the main concern of highway departments is not exceeding maximum axel loads.

Worrying about the amount of wear commuters are responsible for is just a distraction.

It's like a toddler jumping on your mattress vs a 350 lb offensive-lineman doing it. They both technically cause some amount of wear, but it's not worth figuring out the proportions.

Look all you want, but road maintenance costs are primarily a subsidy for the trucking industry, and by extension the businesses that rely on them.

I can't see a plausible argument that cities consume a disproportionate amount of the country's truck traffic. It seems like Suburban malls and supermarkets require pretty much exactly proportionate truck traffic to their city counter-parts. Moreover, manufacture is not particular concentrated in cities so that too gets equal coverage in suburbs. And all of this stuff requires proportionately more miles driven in the suburbs due to the lower density.

I don't know if cities consume more Kambucha than suburbs but if they do, I assume that suburbs consume some other equivalently.

The 80,000lb trucks aren't supplying the inner-city bodegas, they're supplying the out-of-town malls the suburb model relies on. I agree with getting road use charged in line with what it costs, but the result is going to be that the cities stop subsidizing the suburbs so much.

Traffic on roads could stop tomorrow and you'd still need to resurface the entirety of the road network anywhere with a winter season every 5-10 years. Thermal expansion and contraction are serious forces for infrastructure, outweighing traffic in most places I imagine (if most places aren't large cities). Didn't matter much back when we used brick or dirt.

Sure, but they do contribute to the cost of maintaining roads. We need to figure out roughly what percentage of road maintenance costs come from vehicles and charge individual vehicles based on their rough contribution to maintenance costs. It's not a terribly hard calculation, especially since you can directly compare with roads that are infrequently used by trucks.

This reminds me of a blog post about the unsustainability of suburbs — https://mikethemadbiologist.com/2017/03/20/the-fiscal-unsust...

Even if this $1.5m figure is wildly inflated, calculate how few people live on a given mile in the suburbs, a conservative estimate on how much it costs to maintain a road, and the numbers just don't add up.

The suburbs were a ponzi scheme and the bottom is about to fall out.

Or maybe how much road costs in the USA is a bit of a strawman version of how much road costs.

Come on, some remote villages in the third world have paved roads to them.

The third world has a lot more miles of dirt roads than paved roads. The slightly more expencive gravel roads are fine for suburban cul-de-sac‘a / side streets that don’t get that much traffic.

They kick up a shitload of dust so everything is dirty all of the time. They also become unusable/get destroyed in the rain. It makes sense for rural roads since the expense is massive and the dust not so much of an issue.

The dust is much less when speeds are kept lower, such as suburban cul-de-sacs as GP states. Dust can be further mitigated with an annual oil coat.

A well built gravel road will have a decent amount of rock which drains in the rain without turning to mud, culverts are needed on the steeper slopes to limit erosion.

While the total cost is much less than asphalt, dirt roads do need more regular maintenance which municipalities frequently try to skimp on.

A good read of the pro's and con's: https://www.epa.gov/sites/production/files/2015-10/documents...

And in the USA some rural areas have been "unpaving" roads because they have done the financial math : https://www.governing.com/topics/transportation-infrastructu...

https://www.nap.edu/read/21935/chapter/1

very limited discussion a few years ago: https://news.ycombinator.com/item?id=15272140

You'd be surprised how many unpaved roads there are. Even in Europe

https://i.redd.it/4xau5auzqg741.png

The suburbs will maintain their own roads before the bottom falls out. low income suburbs probably will not survive, but there's no law that says they cant have shitty roads that require a jeep to drive on

when the roads require a jeep to drive on, it's no longer a suburb - it's the country. the promise of the suburbs is that it's all the luxuries of city living, with all the space of rural living. Losing the amenities of the city is exactly how i would interpret "the bottom falling out"

Middle- to upper-middle-class suburbs will still exist, they'll just be a municipality a few miles over, where all the houses and roads are 25 years newer, and the long tail of opex costs hasn't quite hit as bad yet. It will, eventually.

If a suburb can attract some retail or office space or manufacturing, they can be like Irvine or Tysons or Bloomington -- the suburbs that have made it. Those that cannot will accumulate the same problems with fiscal sustainability that inner cities once did.

High income suburbs will struggle, too. Gotta pay for the roads somehow if federal subsidies stop trickling in. People on HN talk about moving to texas on taxes alone all the time.

To be fair, suburbia was supported as a potential recovery effort following a nuclear war.[0] Its difficult to immediately urbanize people's lives. We agree there are accelerating maintenance costs, but suspect we don't see the same opportunity cost.

[0] https://scholar.google.com/scholar?lookup=0&q=Disaster+and+d...

I also think people underestimate the desire of men to have their wives and childern living in the suburbs that would survive if a nuclear bomb hit the downtown. By the mid 60's there were so many bombs that this did not make much sense any more, but the roads were already built and there are some nice things about having a large house and a yard.

This is no joke. My father used a map of likely nuclear fallout when choosing where his family would live.

Lots of shade thrown towards people living in suburbia on here. Maybe not everyone wants to live in a (rented) closet sized apartment in a major city, complete with all the noise pollution, actual pollution, crime rates, and a lingering piss-smell 24/7, and all for the low price of _more than owning a house_?

>> and all for the low price of _more than owning a house_?

I didnt read much judgement in th parent post, but it does imply suburbia is subsidized because it has higher infrastructure cost per dollar of tax revenue. The was a study on that very thing a couple years ago IIRC and they found the most solvent towns and cities are actually the higher density ones even if they are lower income areas.

Are you thinking of dollar revenue as an average OR considering suburbian dollar revenue separate? You'd think the suburbia also brings in more cash to the government (I got no sources).

It really doesn't, on a per acre basis.

https://www.strongtowns.org/journal/2018/2/1/the-surprising-...

The discussion was about per-person costs, so per-acre revenues are irrelevant.

You can have cities configured to have more or less people per acre.

It turns out that having more of them per acre is more cost effective.

well, people in suburbia get their infrastructure subsidized by everyone and in addition are destroying the planet, people in cities are paying artificially super-high rent to the landowning class. it seems like we could solve both these problems at the same time and change the value proposition here.

Ideally, this discussion would not be emotional, but simply one of saying "hey, we should all be free to live like we want, as long as we're willing to pay the associated costs".

I live in a city, and I love cars. The issue isn't density, its road damage caused by long and short haul trucking. The shade being thrown towards the suburbs is because some people haven't learned the real enemy is (as almost always) crony capitalism that subsidizes trucking by distributing the costs of roads and road repair onto the local people, while the trucks do the real damage.

It would be preferable that rail be used for transportation and it's unfortunate that trucking in particular gets subsidized.

However, I don't think your argument justifies that American policy prejudice towards cars and suburbs. Suburbs involve more roads - trucks may the force that mainly consumes roads but of course the higher the road-to-people ratio is, the more those roads are going to be consumed by those trucks. Which is to say, of course cars and trucks both go to the far suburbs and the nowhere's villes around the country and of course these trips are part of maintaining these places.

Moreover, if we moved to more rail transit, the little towns would be more in trouble because rail tends to require larger loads and so would raise the price of goods in far suburban malls and such.

The real damage to suburban roads is old man winter.

I don't think anyone cares if you prefer to live rural, the problem is suburbanites having their yard, big house and pool, then every workday commuting into the city where they expect urban dwellers to subsidize the parking spot and eat all the death, destruction and pollution their hunks of metal bring along.

It's like I'm happy to have the walkable grocery store and 24/7 piss smell, but when feeling adventurous driving out to the suburbs to set up camp in your garden.

they expect urban dwellers to subsidize the parking spot

I think most urban commuter parking is paid, whether public or private, and the expectation is that a city charges appropriate property taxes on commercial buildings to cover any costs imposed by commuters.

Also, the more road there is, the more pipes, wires, sewers have to be, and the distance all the water and sewage needs to be moved is longer.

I think this is the real issue. I've witnessed that the problem is lack of maintenance on roads. Instead of taking care of issues as they arise, like patching cracks and small holes, they're left to just grow and spread and before you know it the entire road is garbage and needs to be repaved. If we took care of the roads they would last longer and over time would alleviate funds for other expenses. Not to mention that it seems work on pipes under the roads are never worked on until a few months after it's been repaved, which completely destroys a new road and throws all that money down the gutter.

Isn't that under "Resurface existing lane" and "Improve shoulder"? Yes there are other costs associated with road upkeep, from vegetation trimming to pothole repairs. But I would think the first two are rather major parts of upkeep. To make things easy, assume a 10 year interval between these maintenance items so divide those line items by 10 for the annual cost.

Definitely not a small number considering the installed road base…

>This does not address a larger question: how much does a mile of road cost to keep?

Half of that design chart is for reconstruction and repaving. What else are you looking for?

>an enormous civilizational overhead

You could eliminate suburbia overnight, and demand for those suburban and rural highways will still be there, since cities generally need things delivered from outside (like food) in order to continue being cities.

Yeah, my town resurfaces streets either when they qualify for federal funds or when it is an emergency.

also versus the cost of a mile of rail

The cost should be measured in part by death. Car accidents are the leading cause of death of Americans under the age of 25: https://www.cdc.gov/injury/images/lc-charts/leading_causes_o...

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