I'm more upset about them not paying for the minerals they dig up. We've let a lot of money out the door for very little return.

That's a fairly contentious subject. Yes, fuel taxes often pay for roads; but they also are used for other purposes, as well as to incentivize behavior. Trying to reduce carbon output? Make carbon-based fuels more expensive to purchase, and let the market optimize for alternatives.

They may not drive their enormous mining trucks on public roads, but they benefit from the society (including other public roads) that our taxes support. Plus it's absurd that we're incentivising the use of fossil fuels at all, let alone to dig up fossil fuels.

If the stated goal of a rule is X, it's entirely reasonable to request an exemption based on how you act relative to X. As a matter of principle, I object to denying said exemption because the request comes from the requester's position on Y.

In this particular case, if the tax is indeed levied on the basis of how it impacts road use and repairs, it's perfectly fair to exempt fuel meant to be used only in private property, irrespectively of how I feel about its polluting nature.

I do agree it's absurd that we don't disincentivize the use of fossil fuels, and the mining of said fuels in general, but two wrongs don't make a right.

How do they get their vehicles and equipment to the non public sections of roads?

Keep mind these are trucks with tires that are more than twice as tall as you or I. They were shipped there, oversized, by semi and assembled on-site. The semi that moved it paid its fuel/road/use tax, so taxing the truck being shipped as well amounts to double taxation. Not that there's necessarily anything wrong with that in this case. In California, any vehicle that travels on, or over (as in, shipped on a truck) must legally be registered with the DMV, regardless of if it will be run on public roads, or not. California's car culture has resulted in large race tracks on private land which may be the only place some motorcycles and other racing vehicles will be used. Still have to pay the car tax on it though.

What if cars are imported to a California port, for sale in other states? Do they all need to be registered as soon as they arrive?

Transported by trucks that do pay road taxes

By that measure everyone benefits from public roads and should pay fuel tax even if they aren’t driving on them. That makes no sense.

You know farmers are exempt from diesel tax for farm equipment too, right?

At least in the US, fuel taxes only partially cover road costs. Even if they did, fuel taxes hit more than just vehicles on roads (boats, lawnmowers, etc.) so it’s not that clear cut

I can't talk for anywhere else, but historically in the UK, all tax went into a central pot. More recently cigarette tax is earmarked for the NHS and VED (Vehicle Emission Duty [thought of popularly as Road Tax]) is ear marked for transport improvements. I'm not a fan of this - as a cyclist I was often told (at least a few times a year) but drives that I should get of the road as I dont pay for it. Ignoring the fact that I owned two cars and paid a lot of tax...

That seems to be specific to the UK. In most places I've looked into this, taxes on things like fuel and cigarettes do not go into the general fund. The reason is the taxes are meant to achieve something, and so they go towards that purpose. Otherwise it would present a corrupting influence that misaligns the incentive of the government going forward.

In the US, fuel taxes are earmarked for road building and repair, but aren't enough to pay for them at either the federal or state level. That completely ignores the negative externality of carbon emission.

Meanwhile, in a few states, cigarette taxes are actually targeted at the negative externality: health problems, including secondary smoke.

So I guess it depends on what you want to achieve. Failing to tax a negative externality like carbon emissions would seem to be corrupting influence that misaligns the entire economy.

I came across them too, I usually respond that they are paying for damage to the road their car causes. Bikes don't.

"Isn't the point of a fuel tax to pay for road repairs"

Depends on the country.

In the UK it just goes into the big tax pot. That obviously doesn't stop various groups claiming they pay for the roads. Comments normally aimed at cyclists.

And in the UK, tractors are exempt from (may be just a reduced level?) fuel duty, they can still use the road though.

It really should be for offsetting the externalities from burning fossil fuels _and_ wear on the road, so if you burn it, you clean it up.