Does the equation not also depend on non-damage-related costs for roads? How much of the total cost of a road arises from resurfacing costs? If a large portion of the costs are unrelated to repairing damage (initial construction, drainage, cabling, signage, traffic management, monitoring, probably a host of others), then it could still make sense to charge cars nearly as much as trucks.

I don’t have the data to argue either way.

This. It's nuts to build infrastructure and then punish its use. Overuse or non-propertional damage should be punished, of course. Infrastructure costs should be divided by its users (or society as a whole) and then users should be encouraged to maximize utilisation.

Imagine someone would do this to bike lanes, railroads, or optical fiber. The facts that gasoline cars are a problem for the climate and that cars take up too much space to be generally available in dense cities have nothing to do with roads per se.

No - the use of gasoline does not impact the cost of the road. But it can be used to persuade people to use the bike lane next to it. People are amazingly sensitive to costs - check for instance tax benefits. As soon as a product is subsidized by means of a tax rule, people run as fast as they can to get it. Hybrid and now electric cars are a great example (at least in the Netherlands). By having people pay by the mile instead of whether they own a car or now, usage is more evenly charged. You drive a lot? You pay a lot. Even nicer would be to add a charge to the gas prices: your car uses a lot? You pay a lot. But it seems that the gap between buying gas at the pump and riding your car is too wide: people will get a guzzling car regardless. But if you know that every mile you pay 10 cents..? I guess it will get people out of the car very, very quick...

But road usage by cars is not the problem, CO2 emissions is. By doing this kind of punishment-by-proxy the whole taxation becomes ideological (car too big, car too foreign) and loses legitimacy. Keep in mind that in a democracy you shouldn't aspire to force people to do "the right thing", you should aspire to create consensus. A high tax on gasoline is easy to understand and easy to argue for. Double payments, illogical taxation, and "nudging" just pisses people of into the arms of right-wing parties.

Well, not exponentially, it is still just a power law.

But I agree that taxes should be damage-based. Tax those lorries to hell, if they want lower taxes, they should buy one with more axles and more tires per axle.

I would assume they would just raise their prices. Like with shipping containers from China to the rest of the world - prices increased tenfold...

Yes of course. But some will be more competitve by having less weigth-per-axle. So after one replacement-generation of trucks, roads will be in better shape because trucks are less prone to damage them on average. And in general, trucking goods needs to be more expensive anyways to make less pollution transport options like ships and trains more competitive.

Consumers can also be made whole by removing vehicle taxes on cars or subsidizing other modes of transport that consumers use from those trucking price increases.

> Road damage per-axel is proportional to the weight carried by the axel raised to the fourth power!

That's not true. But the truth is even worse than that. The effect is highly non-linear. Depending on type, composition, age and temperature, the road material require minimum load to become plastic. Below that critical load the surface can withstand wear and tear of practically infinite amount of trips (have you ever seen a road where the surface was rubbed away by passing cars?)

Of course, some aging processes continue regardless of whether cars are or are not using roads.

True, but roads decay even in the absence of use. So, there's a cost involved in just having the road available and in good shape; that cost should be shared by all users.

100%.

But do you take into account how much road use is consumed, and what type of roads, and where they are?

If registration fees for large trucks were increased it is likely that the costs would be passed on to the consumer. We would see higher shipping fees and potentially higher prices for goods at stores.

We can debate which we'd rather pay but one way or another the cost would come down to us.

Having the people in a position to reduce the damage be responsible for the cost means they can make sensible decisions. Right now, for example, it makes sense to ship something much farther so you can have a really cheap distribution center outside of town, even in cases where this is more expensive overall.

Wouldn't this be a good economic incentive to buy more locally? Since it sounds like currently shipping costs via trucking are ignoring this externality.

Externality? Who do you think is bringing you food and all the items you buy? Even locally?

The Grenadier Guard?

Currently the complete cost of shipping food includes road damage that is not priced into shipping but instead borne by all citizens. By making those responsible for road damage, pay for it, they have an economic incentive to stop the damage.

Not priced into shipping, but equally borne by all tax payers. If all tax payers benefit through transportation of food and other essentials, that’s not really an externality? The people paying are the ones who benefit?

It's an externality because the people who are paying aren't the people who are causing the damage.

This isn't so much unfair, but it does remove incentives for the shippers to cause less damage to the roads.

A truck damaging the road dis-proportionally is an economic externality [1].

[1] https://en.wikipedia.org/wiki/Externality

Which might push our shipping back to more efficient ways to transport goods and services than caravans of big rigs.

True, but I think the question at hand is how do you apportion cost to those most responsible for it

Sorry to be this guy but Axel is a name and axle is the rotating shaft.

No, "axel" is a figure skating move. (Which is named after a guy.)

Ah yes! My girlfriend did this move a few days ago and I thought of axles lol. I guess they also do them in dance. It looks like a complicated spin no?

You took the words right out of my mouth.

Would also add there is an miles travelled does not equate to time on the road (highway vs local driving) and state funding has biases as well (highway vs local roads, urban vs rural infrastructure)