https://www.citylab.com/transportation/2015/05/debunking-the...
'To be clear, Amazon purchased only the trailers and will use third-party companies for the actual truck cabs and drivers. The original source report did not make clear there was a distinction.'
https://www.technobuffalo.com/2015/12/04/amazon-prime-now-ha...
Presumably Amazon funds paid to delivery services are also used to pay for gas, which therefore indirectly pays for the roads.
You could make a (good) argument that they are underpaying their contract drivers, but nontheless -- everytime they pay a contract driver to drop a package off at your house, Amazon is paying for that gas in their pay to the delivery driver.
The same is true when they use a commercial delivery service at all -- the cost of fuel tax is bundled into the delivery price.
Whether Amazon owns any trucks of their own is immaterial, if they are contracting with Amazom, Amazon is ultimately paying for the fuel (including taxes).
https://frontiergroup.org/reports/fg/who-pays-roads
They pay less for the roads than you or I. You are subsidizing Amazon's business with your taxes.