To give an idea of what this means:
For a 50 tonne semi-trailer with five axles, (⁵⁰⁄₅)⁴ = 10,000 units of damage.
2 tonne vehicle with two axles, 1 unit of damage.
That one truck, only 25 times as heavy as a pretty heavy car, is doing 10,000 times as much damage to the road.
Thus indeed if you have basically any heavy freight at all on a road, the rest is negligible.
It could be that four tires on a truck axle are much more effective at spreading the weight than two car tires. Or it could be that it's not much better, as the forces are still placed on a relatively small area of asphalt.
How this makes cars and trucks compare is, as far as I could understand from the literature when I dug in to it, an untested open question.
There could be a 10,000 factor difference. Or if two tires at each end are spreading the weight over 2x the surface area and you assume that matters, then you have to divide that 10,000 by 2^4 and it's now only 625x as damaging.
I suspect the reason nobody cares enough to test this is that it would still be a gap large enough to make cars insignificant.
> I suspect the reason nobody cares enough to test this is that it would still be a gap large enough to make cars insignificant.
That seems likely, yes.
My main point though is just that the study happened to use truck axles as a measurement and that can't blindly be substituted for car axles. The back of the napkin math is just there to show the difference it can potentially make.
Passenger off-road vehicles with knobby tires might be harder on roads too in a different way than weight.
It would make a significant difference to the calculations, eg 50% wider tires would mean dividing truck severity by 5.
So, getting people out of their cars onto bicycles cuts road maintenance cost.
Because of that, building bike lanes/paths can be cheaper than not building them.
(And 50 tonne trucks are very rare on most city roads, I hope)
As a Michigander, the dictionary does not contain words to express how strongly I disagree with that implication.
As a pedantic side note, this is why your batteries die, the copper leads begins to fatigue and fracture due to stresses from thermal cycling.
The principle that shifting traffic from cars to bikes saves money for the government is a sound one. There'll always be a need for cars for some things -- probably not gonna have ambulance bikes, and of course deliveries for anything big needs a car/truck -- but you can certainly reduce the need. Especially with ebikes making biking more convenient and accessible.
But not every journey needs to be done by car.
The point isn't to individually shame unwilling people out of their cars. The point is to make biking a real, viable transportation mode for short/medium distance trips for most people in urban or suburban areas. It's entirely possible to do this with the right infrastructure.
Once you do that, people will choose biking of their own accord, because it makes sense.
That isn’t an original idea. See for example https://www.vabike.org/vehicle-weight-and-road-damage/ (2009)
Also, if in Google “50 ton 5-axle truck” I get trucks that I rarely see on roads in Europe. Reading https://www.jpisla.es/resources/Download+JPIsla+20130106+Pes..., that’s because t most countries don’t allow them on roads.
Add an empty trailer and you get 35 tons (5 axles, 2400 units of damage). US max allowed is 80 tons, for a whopping 65,536 units of damage.
I don't know how full they are, but I see 5-axle tractor-trailers on highways all the time in the US, and also locally doing last-mile deliveries to larger businesses like supermarkets and home improvement stores.
I guess the differences in allowed weights might account for why US roads are often in worse shape than many in Europe, though I assume vastly different maintenance schedules play a large part as well.
[0] https://www.tcsfuel.com/blog/truck-weight-classification/
Max US ordinary large truck loading is 80k lbs, or 40 tons.
(Source, I trained as a civil engineer. Units in us practice were all over the place, but kip was generally the one that got used the most.)
https://en.wikipedia.org/wiki/Large_goods_vehicle
https://assets.publishing.service.gov.uk/government/uploads/...
As long as the roads are built to sustain those trucks the cars are negligible. So until cars are the big wear item, moving people to bikes is pointless from a road wear perspective.
Racetracks don't carry freight, but the surface does goes bad in a couple decades.
There's many more passenger cars than freight trucks on the roads.
It doesn't change the math all that much, but the 1-to-1 comparisons in the thread didn't account for this factor.
There's safety, exhaust emissions, tyre and brake particles, noise, etc. I'm sure some of them don't have a linear relationship either.
One of the biggest upsides to taxing vehicle weight could be to counter purchasing decisions that have shifted to larger vehicles that no longer comfortably fit in parking spaces but ride better over ridiculous speed bumps and give drivers literally the opportunity to look down on others.
Taxing vehicle weight also doesn't have the privacy implications that taxing miles driven beyond fuel consumption does. It's always struck me as one of the more sensible aspects to tax.
Add lightness, as I believe Colin Chapman put it.
1) The primary concern here is per capita road damage. If that's agreed, why is the conversation not about improving the resiliency of roads?
2) Why would the adoption of new technology automatically subject you to draconian taxes that have nothing to do with that new technology? I understand infrastructure needs to be paid for, but this is simply a cash-grab by politicians. If people started jogging to destinations rather than use cars, would it be acceptable for the government to charge a "jogging transportation tax"?
This is generally a bad thing, but very concretely it led to road traffic growing much faster than rail traffic (or canal ship traffic) even in countries with a very dense rail network.
Comparing this with free public education, by not charging user fees to attend school, we are subsidizing (a) having children, and (b) educating them at the expense of the childless and I guess people who don’t want to educate their kids. We subsidize those because we believe they are truly public goods that are better for everyone in the long run. Encouraging people to drive more and ship more things by truck is not necessarily better for everyone.
Hence greatly increasing chances of finding better or any employment and at least partially reducing pressure employers can come up with.
...
You load sixteen tons, what do you get?
Another day older and deeper in debt
Saint Peter don't you call me 'cause I can't go
I owe my soul to the company store
...To each their own.
That said, you should listen to the podcast “Nice White Parents.” It points out that this model of underfunding the schools and making up for it with donations is essentially letting wealthy families buy their way out of the problem while leaving disadvantaged students behind.
I can't help but see this as a regressive use tax in many ways, since it'll likely apply to lower value items at a higher proportion which is what poorer people would be buying. The end user pays in either case, but doing it through taxation policy allows for a measured approach.
Here in Sydney we just opened a tolled tunnel, and to ease congestion up above on the older commuter road all trucks must use this tunnel. I don't know all the factors but it sounds like the best option for the people, they have a choice and trucks pay their way.
There is no benefit to discouraging use of highways at night, or uncongested suburban/rural roads. The thing you really want to prevent is congestion.
And even that is not inherently best solved through punitive fees. If you can reduce congestion by e.g. building more housing near where people work so they don't have to commute as far, that's preferable to levying fees the drivers can't avoid because a viable alternative to a long commute isn't actually available.
Sometimes turning a four lane road into a six lane road really does resolve the congestion, even accounting for the increase in use that comes from the reduction in congestion. And then you don't gain anything by discouraging use there.
The number of cases where you actually want to discourage use is very small, to the point that they may not even really exist, given that most uses are productive (and already have to overcome the inherent cost in fuel and time). The best case for it would be something like Manhattan during rush hour, but even there you might be better off to use the carrot instead of the stick and e.g. stop charging fees for use of the subway.
The world doesn't heat up slower if we manage to use roads 100% during nighttime too.
Same for wear and tear.
We're talking about electric vehicles which don't have that. That issue can obviously be solved for gasoline and diesel vehicles via fuel taxes (which encourage people to buy electric vehicles).
> Same for wear and tear.
As discussed, nearly all of the wear and tear is a result of large heavy vehicles and the amount caused by passenger vehicles is negligible.
Furthermore, continuing to build more travel lanes to alleviate congestion has been shown to simply lead to more traffic. It’s a circular problem.
We are finally seeing this turn around in a very painful way in Silicon Valley. There’s no longer political will, nor is there tax revenue, to keep expanding the highways. As a result, commute times have gone up dramatically. As a further result, over the past decade, I’ve watched previously undesirable near suburbs like Sunnyvale and Santa Clara be bid up dramatically in housing price as people have realized that spending 3 hours per day in their car isn’t worth having a giant house with a giant yard in the far south suburbs like Morgan Hill and Gilroy.
This is like arguing against rope because it was the primary enabler of lynchings.
> Furthermore, continuing to build more travel lanes to alleviate congestion has been shown to simply lead to more traffic. It’s a circular problem.
It isn't. What those studies are showing is that congestion suppresses demand, so if you relieve some of the congestion, some of the demand comes back. So to relieve congestion you'd need enough lanes to carry not the existing level of traffic, but the amount there would be if there wasn't any congestion suppressing it.
This is clearly demonstrated in China where they build multi-lane highways to nowhere as a jobs program and then traffic does not magically appear to fill them.
The problem is that in some places, satisfying all of the demand by only increasing the number of travel lanes would require like twenty travel lanes, which isn't ideal. But that doesn't mean you can't reduce congestion there by adding travel lanes, only that you need other solutions there too. Add a travel lane or two but not ten, build more housing closer to businesses so people don't have to commute as far, stop charging user fees for mass transit etc. By doing these things together you can alleviate congestion without needing twenty lane highways.
> We are finally seeing this turn around in a very painful way in Silicon Valley.
The problem there is totally unambiguously not "insufficient highways" and is in fact "insufficient housing" which induces those long commutes for whoever can't afford the existing housing close to the city where the jobs are (and also outrageous housing costs for the housing that is, because nobody wants that commute). Build more housing.
If everyone rode bikes or the bus 90% of the time, there would be mostly empty roads in the 10% of time that they do use a car.
If you had to pay a significant price per km in congested areas, you'd probably drive less, but it would be a nicer experience when you do drive.
Possible formula to account for all the variables:
annual tax = F * (A + [BC{D^E} ] )
A = constant for non-loading based degradation (frost heave, slope maintenance). Base tax
B = constant to scale the following terms
C = distance driven in km
D = axial weight
E = exponent to account for non-linear relationship of axial weight to road degradation
F = adjustment for usage (could adjust for anything - user type, income class, vehicle class, etc etc)
A lot it is caused (around here anyway) by water permeating and expanding as it freezes.
In South Australia we get temperature below zero maybe once every 10 years.
Victoria has some snowfields, but they are a relativity small area.
Bitumen damage from melting is a real issue though. See the pics on https://www.abc.net.au/news/2018-07-05/melting-road-in-far-n...
It is also much more relevant in places with sub-zero nights, i.e. a thaw/frost cycle. In relatively warm places like Australia this effect does not occur. Roads are much cheaper per km than in places with snow/ice, even with heavy vehicles.
I’ve seen weight limit signs on certain roads, I wonder if instead they should be PSI limits?
So that would mean the first still has to pay 5x the tax of the latter.