And yet the average age of the car in Denmark is 8.9 years [1]. For comparison Germany is at 9.3 year, and US is at 11.6 years [2]

[1] http://www.aut.fi/en/statistics/international_statistics/ave... [2] https://www.statista.com/statistics/261881/average-age-of-li...

But anyway, these average ages may be due to little used old cars being taken out of registry, to avoid annual fixed taxes? This has not much impact on the average age of cars used in daily traffic.

FWIW, I'm from Finland, also with a history of high car purchase taxes, and the average in above data is almost 12 years. The oldest cars, however, have lower annual car tax (they had the highest tax at purchase time).

BTW I understand Denmark was about to lower the car purchase tax from 180 % to 100 % or so?

As for your other argument - both reports count "vehicles in use" (ACEA) or "vehicles in operation" (US)

Also, the "vehicle in use" is not necessarily such a clear definition.

For instance, several of my colleagues own historical vehicles from 1960's and 1970's which are "museum registered", which here means that they must be at least 30 years old, can be used only on 30 days each year, and they are not subject to annual "MOT check" (but a different kind of check every 2-4 years).

Are they included in the "vehicle in use" statistic? I don't know. And I don't know what are the specific regulations for similar vehicles in other countries. Because the cars are 40-50 years old, even a not very big number of them would skew the statistics of average age of cars.

Renault actually advertised this at the time: "will rust like a fish", with a picture of a car immersed in water. Seems to be legitimate: corrosion problems have become much more rare.

This statement requires a bit more detail. It wasn't a flat tax rate, it was graduated, so below a certain price, there was a lower rate (105% IIRC), to incentivize smaller cheaper cars, and as a luxury tax on expensive vehicles.

As it is now, the rate is 85% below ~190K DKK and 150% of the value above that. The cutover has been steadily going up over a couple of years now.

So no, it has not ever been a flat 180%, as some people like to claim. It's still high, but there are tons of cars out there that don't hit the tax cutover point, even family cars.

Edit: And the rates are lower for motorcycles, hybrid cars and such.

I have been wondering for a little while now if the extreme libertarian position on private roads has been vindicated. I am not sure yet, but it seems possible where once it was ridiculous.

Starting with (let us say) World war two, cities and states built out substantial, publicly funded roads and road networks in order to connect up newly developed sub-urban centres that were designed for car owners. These new centres were affordable for the emerging middle classes, who migrated there en-masse. This co-incided with the baby-boom, which was partly possible due to cheap housing.

But this left the inner cities to die slow deaths where immigration was not high. (Side note: This is more true of American towns, in Australia I don't know that we had the dramatic changes seen in the highly industrialised centres of the USA.) So it possibly boosted the middle class at the expense of the lower class (?) and it created huge urban sprawl.

Would private roads, paid for collectively by the developers or residents of those suburbs, have helped to alleviate or reduce the problems outlined above?

I am spitballing here, and it is a little off-topic, but please indulge me!

I live here and have to pay the tolls but I still prefer it from a "user pays" justice POV.

It doesn't have to be privatized though - Singapore is introducing a GPS-distance-based congestion charge on their roads ("ERP 2" if you want to Google it)

In the United States, it was somewhat more complex than that. The highway network was and is primarily part of the nation's military defense infrastructure, so that weapons and personnel can be moved around in a time of crisis. (Something from Germany that impressed the U.S. during WWII.)

This is why the system is named after a general who was also a president ("The Eisenhower Interstate Highway System").

It's also the reason why the rails are not usually removed from abandoned railroads anymore: So they can be rehabbed in an emergency.

There's also a lot of social studies involved, including the baby boom.

Like all large human endeavors, it's messy.

[Edit to add:]

Would private roads, paid for collectively by the developers or residents of those suburbs, have helped to alleviate or reduce the problems outlined above?

One of the many contributing factors to the U.S. Civil War was the notion that the North wanted to shed its remaining privatized roads and federalize the whole thing, while the South wanted entirely private road systems.

You are right. I am not contesting the Highway system, which actually still seems to be a good case for Federal public spending, both because it benefits the military and because it is inter-state.

My point is entirely regarding the roads that were built out from the dense urban cores to connect with sub-urbs, and the roads built to connect sub-urbs with one another, and those inside of suburbs too. If these were paid for by those who used them (and not inner-city dwellers) then perhaps urban sprawl would not have happened, and we would have saved ourselves from a whole host of externalities we are only discovering now.

Well, they are. That's the 9/10th of a cent that drivers pay on each gallon of gas they purchase.

IMO, it should be closer to an even five cents, with half of it going to mass transit. But then I also drank milk and Pepsi mixed together when I was a kid, so I'm not exactly reliable.

There are also state gasoline taxes, vehicle weight fees (for commercial interstate trucks) registration fees, and tolls[2].

1. https://en.wikipedia.org/wiki/Highway_Trust_Fund 2. https://www.citylab.com/transportation/2017/07/us-transporta...