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Road damage goes by the 4th power of the axle weight. Increase the axle weight by 5.6 times, you get 1000 times as much damage.

A quick Google shows that 30,000 lbs seems a reasonable weight for a bus, on two axles *at best* you are at 15,000 per axle. For the bus to be less than 1000 times as damaging as the average car, the average car would have to have an axle weight of almost 2700 lbs. No way that's average.

So, yeah, a bus really *does* cause damage equivalent to thousands of cars.

http://www.pavementinteractive...

Because road wear is a function of the fourth power of the weight, the fees should be:

A 540-pound motorcycle pays $0.0013/mile
A 3,470-pound SUV pays $0.347/mile
An 80,000 pound semi trailer pays $4,252/mile

There are two problems with your system, which is why It's never been implemented.

1. The minute you tax by the mile people will all start faking their mileage. Its easy to roll back the odometer and hard to enforce on a large scale.

2. Everything we buy is delivered by a lorry. If we taxed lorries even more then we will have to pay much higher prices at the till for everything.

The closest thing to the system you describe are fuel taxes. A person who travels more will buy more fuel, also heavier cars will use more fuel. This system also has the benefit of being easily implemented and enforced.

Because road wear is a function of the fourth power of the weight, the fees should be:

A 540-pound motorcycle pays $0.0013/mile

A 3,470-pound SUV pays $0.347/mile

An 80,000 pound semi trailer pays $4,252/mile

But trucks do have a lot more wheels, which means the road wear is 1/16th (for 8 wheels) to 1/256th (for 16 wheels) - right?
So the actual price will be about 16$ per mile.

Because road wear is a function of the fourth power of the weight, the fees should be:

A 540-pound motorcycle pays $0.0013/mile
An 80,000 pound semi trailer pays $4,252/mile

Oh yeah? How do you think your milk and veggies get to you? Or
the gasoline for your motorcycle? We don't build roads just so you
can move your body in useless pursuit of tourism.

Because road wear is a function of the fourth power of the weight, the fees should be:

A 540-pound motorcycle pays $0.0013/mile
A 3,470-pound SUV pays $0.347/mile
An 80,000 pound semi trailer pays $4,252/mile

CItations:

http://www.pavementinteractive...

https://www.apta.com/resources...

There are many more.

The thrust of all of them is that _transit_ buses (in particular) _are_ a significant problem with axle loading often in excess of 22,000 pounds and almost always exceeding US federal highway recommendations (ESALs aren't enforced as rigorously in the USA as in the EU)

Several US cities have published engineering reports specifically calling out transit busses as being the single largest contributor to road maintenance costs and making the case that pushing for increased use of public transportation must go hand in hand with development of light rail (streetcars) and/or significant increases in roadbuilding investment. (ie, most of the cost of maintaining roads that are heavily used by high ESAL vehicles is because the roadbeds were never designed for the kinds of loads they now receive)

As for the 20 ton pointer: A modern London Double Decker weighs approximately 12 (conventional) to 14 (hybrid propulsion) tons (unladen) , with single deckers being in the 9-16 ton range. These are all short wheelbase units for operating in much narrower and more crowded streets than the average USA one. Once laden with passengers they all easily top 20 tons

The 2nd report above gives the empty and laden masses of USA/Canadian busses, which in general can carry more passengers than their european equivalents due to greater length. Pay particular attention to the fully laden weights of the buses in that report.

As for 400hp busses and 200hp cars - urban transit vehicles have engines closely matches to their working load. It's uncommon to see transit bus engines larger than 250hp - and whilst there are plenty of 200hp+ cars on sale, the vast majority of vehicles sold in the USA are well under that figure (and in any case their mass seldom goes over 2 tons). Light trucks are another matter and higher fuel prices are proving to be darwinian on those.

A Smart car weighs about 1800 lbs. A Dodge Durango weighs about 6500 lbs. The accepted rule-of-thumb is that road damage increases as the 4th power of weight. So, the Durango causes ~170 times more road wear. Even if you don't accept that full number, it's still a very significant difference.

Weight-based fees for passenger vehicles really, really make a lot of sense.

Tires are almost silent on paved roads

The hell they are. Tire noise accounts for 70-90% of overall noise energy when travelling over 50mph.

Have someone put their car in neutral and turn the engine off as they roll down a hill toward you.

I will notice the car getting louder and louder as its speed increases. What's your point?

You will find that your napkin estimates are incorrect. A truck will do up to thousands of times more damage to the roads than cars.

http://www.pavementinteractive...

Damage to roads is usually considered proportional to the fourth power of the axle weight. Cars are generally calculated to average 2 tons, even "big" SUVs aren't usually as heavy as their size might imply. I don't like SUVs either, but that's no excuse for bad policy. According to this GAO report, a fully-loaded tractor-trailer does as much damage to the roads as at least 9,600 cars. Fuel consumption is proportional to weight at low speeds, and at higher speeds wind resistance rises as the square of velocity; it is obvious just looking at the exponents that a simple fuel tax will not tax large vehicles in proportion to the damage that they cause. Taxing consumers as opposed to commercial vehicles is a terrible idea; it would have the effect of subsidizing heavy vehicular traffic. If we're going to subsidize freight, we should invest in rail infrastructure.

If you call a factor of 11 a small degree, sure.

A 133.3 kN (30,000 lb) single axle does about 11 times more damage than a 133.3 kN (30,000 lb) tandem axle (7.9/0.703 11).

http://www.pavementinteractive...

The damage is caused by the road surface flexing. If the load is spread out over a larger area then less damage is caused.
The reason for the exponential damage increase is because if the road flexes twice as much it causes 16x the damage.

Also consider that while a large truck does carry a significant amount of weight, they also distribute it over a significantly larger contact patch. While I will grant you that load on the asphalt is still higher than most cars, it's not nearly as straight forward as one might think. If someone with more time could google a comparison, that would be very enlightening.

Damage done to the road rises exponentially with the load. The rule of thumb is damage to the road is proportional to (gross weight / # axles)^4. A single fully loaded tractor trailer can do as much damage to a road as 1000 passenger cars. So I don't know if the higher fuel tax trucks pay completely offsets the additional wear they put on the roads.

See http://www.pavementinteractive...

in nearly all states, collected gas tax doesn't actually get spent on roads

"[E]ven if [fuel tax] funds were fully devoted to highways, total user fee revenue accounted for only 65 percent of all funds set aside for highways in 2007."

Therefore, if we want the roads to start paying for themselves, we'll need to raise the gas tax, increase other taxes or fees, and/or allow some roads to return to nature so we no longer have to maintain them.

Because air pollution is proportional to the amount of fuel burned, the gas tax is a good way to pay for air pollution, which costs us up to $1,600 per person annually in medical costs, lost days of work, and so on. It's also the least bad way to pay for global warming. Ideally, the gas tax should also vary according to the quality of the vehicle's emissions system, because older cars pollute more per gallon of gasoline than newer cars.

But the gas tax isn't a good way to pay for road wear, which is proportional to the 4th power of the axle weight. For that we'd need a mileage fee that varies according to vehicle type or weight.

And the gas tax also isn't an effective way to manage traffic congestion, which varies by the hour and the location. For that, we would need some kind of congestion pricing such as variable express tolls or a mileage fee coupled with information about when and where you drove (but there are privacy concerns with that option).

So if the goal is for the roads to pay for themselves, then the most efficient and equitable way to achieve this goal in a capitalist society where people pay each according to the benefit they receive and the burden they place on the system, is with not just a gas tax but also some kind of mileage fee and congestion pricing. Then we could lower transportation sales taxes such as Prop K in San Francisco or Measure R in Los Angeles.

The law was determined empirically, but professionally enough.

(I can wish the info above will increase your willingness to look a bit more for info than whatever your DOT responsibilities require you to ... I don't know, possibly to delay the onset of the Peter's principle. May be good for you and for the citizens of your state)

The law was determined empirically, but professionally enough.

(I can wish the info above will increase your willingness to look a bit more for info than whatever your DOT responsibilities require you to ... I don't know, possibly to delay the onset of the Peter's principle. May be good for you and for the citizens of your state)

Really? 99%?

Could you cite that?

Thanks.

I don't know if it actually works out to 99%, but in general, road wear rises with the 4th power of axle weight, so trucks account for the lion's share of wear and tear on roads:
http://www.pavementinteractive.org/article/equivalent-single-axle-load/

On the other hand, 99% might not be that far off:

Roads are usually designed assuming that a single axle on a big truck carries a maximum of 18,000 pounds. Compared to a typical car carrying 2,000 pounds per axle, a fully loaded truck stresses the road surface 6,561 times as much.
  http://www.straightdope.com/columns/read/2974/why-cant-they-make-highways-last-forever

If the government didn't depend so much on fuel taxes, they wouldn't care so much about bootlegging.

A mileage-based tax based on the weight of the vehicle would also solve the problem that a 2-ton car causes 16 times as much road wear per mile as a 1-ton car, but only pays about twice as much in fuel taxes.

Putting an environmental impact fee (tax) on fuel would be a more reliable compensation for your impact than GPS.

Actually, the gas tax only covers your emissions. It doesn't cover your impact on traffic congestion, which is higher when the road is congested or approaching it; it doesn't cover wear and tear on the roads, which is proportional to the fourth power of the weight of the vehicle (the gas tax is only proportional to the first power of the weight of the vehicle); and it doesn't correct for the fact that bridges are much more expensive to construct and maintain than at-grade roads in rural areas.

Because road wear is proportional to the fourth power of the weight of the vehicle, make the 4,000 lbs SUV owner pay 16 times as much in taxes as the 2,000 lbs small car owner. Pretty soon we'll see fewer SUVs on the roads, and all because of a fair, well-justified tax as opposed to new, arbitrary regulations.

But you are forgetting, this approach will cost you 28 times as much overall once the general contractors, last mile delivery drivers and other service truck drivers have to start eating a 16x tax hike. Otherwise, were are you going to get your milk, eggs and internet from? Last time I checked, your milk and eggs were delivered by truck, semi or heavy duty box depending on your store, and AT&T or Comcast won't dispatch techs in a prius.

Because road wear is proportional to the fourth power of the weight of the vehicle, make the 4,000 lbs SUV owner pay 16 times as much in taxes as the 2,000 lbs small car owner. Pretty soon we'll see fewer SUVs on the roads, and all because of a fair, well-justified tax as opposed to new, arbitrary regulations.

Maybe you could, you know, let people buy the vehicles they want to buy and then if gas is expensive most won't buy gas guzzlers?

First, we would need to internalize the negative externalities of gasoline usage into the price of gasoline. For example, air pollution costs us up to $1600 per person annually.

Another problem is that road wear is proportional to the 4th power of the vehicle weight, while gasoline usage (and therefore gas taxes) is more linear.

Once people start paying the full costs of driving, then they can start making rational choices about which car to drive.

I pay for the roads with my fuel taxes.

I read somewhere that road wear is estimated as proportional to the fourth power of axle weight. The axle weight of a car and its driver is at least ten times that of a bike plus rider, meaning a car does ten thousand times as much wear. So even assuming that three-fourths of the fuel price is tax, as it is in some countries of Europe, the rounding error on my sales tax is probably enough to cover the wear that my bicycle does to the roads.

Actually, it's worse than that. The general rule of thumb is the ratio to the fourth power.

http://pavementinteractive.org/index.php?title=ESAL

I didn't believe what you said, so I searched for some facts. From what I see (here), it's actually the fourth power of axle load. It also correlates with speed - slower speeds cause more damage. So this might be the germ of a good idea, though probably hard to enforce and collect fairly.

A gas or diesel tax is relatively simple to measure and collect, and it correlates directly to one quantity that we wish to control - carbon emissions. However, wear and tear on roads is also a measurable expense, and an electric vehicle will cause as much as a gasoline vehicle of the same weight. So I think that there is a role for this sort of tax, if done correctly based on axle loading.

Actually, the equivalent single axle load (ESAL) is 0.000019425 for the Fit and 0.0007716 for the F-150 (assuming equal distribution on axles). So really that F-150 does over 39 times the damage the Fit does. To be fair though, that's nothing compared to semis for which the legal single axle load is 18,000lbs for an ESAL of 1.0. Either way though, it doesn't take away from the fact they are doing the same amount of damage by traveling the same number of miles they were previously, and paying less to do so which is the entire point of the VMT tax. ESALs explained. http://pavementinteractive.org/index.php?title=ESAL

The damage a vehicle does to a road is (broadly) proportional to the fourth power of its axle load for each of its axles. For a more complete discussion click here. That's not a factor of four, that's exponential. Double the weight on the axles and you do sixteen times the damage to the road. That means that a average loaded semi(articulated lorry for the UKers) or a bus does over 1100 times the damage that a ridiculously overloaded (8000lb) Hummer H1 does per trip. A 2500lb Prius is better by about a factor of 105 than the Hummer.

Fuel taxes in the U.S. do not exclusively go to road-maintenance and administrative overhead, some goes to various transportation research and safety research and other things. However, 80% of the federal tax revenue does go to road and bridge construction. 90% of the Interstate Highway System's budget is Federal money. The average gasoline tax is $0.47/gal with a range of 62.8(CA) to 26.4(AK) cents. Diesel is 53.6 average with a range of 70.6(HI) to 24.4(AK). Apparently, Alaska doesn't themselves tax diesel. Obligatory wiki link. Toll roads also get some of this money. While gasoline taxes are slightly lower than diesel taxes (18.4 vs. 24.4, federal) the primary users of diesel are heavies, like semis and buses. This means that automotive users are effectively subsidizing the roads for the heavies, especially as the heavies tend to be more efficient per ton/mile than autos in moving their cargo and tend to stick to the interstates more. The payback is, of course, lower shipping costs for consumer goods. However, and there is always a however, it could also be argued that shifting the cost through an indirect path increases the chance of(read virtually guarantees) additional cost in arbitrage(middle-man suck or, for Civilization players, corruption).

Tolls for commercial vehicles tend to be higher than for automobiles, but not in proportion to their weight, cargo weight, or especially the damage they do to the infrastructure. (See above) The tolls are a tiny percentage of the cost of shipping, especially in time saved which is usually a prime cost factor. The cost of the tolls will simply be rolled into the shipping costs anyways. Lower income drivers will be incentivised to choose alternate routes shifting congestion elsewhere or perhaps abandoning their plans for travel altogether. Even drivers that don't feel the cost as anything but a nuisance may be disincented on principle. Toll roads thus tend to become an infrastructure biased for the wealthy and commercial interests although not strictly to the exclusion of the poor. And everyone pays for them. Just like NFL franchises and operas.

While Eisenhower was impressed by the autobahns that the Nazis built and the speed with which military transport could be carried out on them and sold the Interstate highway system on national security grounds, a knock-on effect was the change it had on society. Suddenly people could have freinds and not just pen pals in other regions. "Those people