I believe that it should the cost to repair roads should be the responsibility of those who cause the damage. Yes, this would raise cost of goods shipped via truck. If you're ordering things that need to be shipped via truck, you should be responsible for that damage.

Why should I be taxed to fix road damage based on a metric that doesn't begin to accurately reflect my actual contribution to the problem?

Additionally, if the trucking industry had to raise rates due to a higher 'road maintenance tax' this may also make more efficient forms of transportation more popular, ie trains.

I am not opposed to the tax, I simply think it's pointless to talk about what it's "for". That's what I meant to convey with the second line. It's a tax. If you don't pay this one, you'll pay another. And the government will spend the money where/how it sees fit.