Difference being that FedEx pays 0 $/km for the roads, but the $/GB and $/GHz will be at the mercy of their cloud provider.
That is really not true at least in the USA. There are all kinds of taxes and fees for using the roads with large trucks. Have you ever seen the weigh stations on the sides of the highway in the US? Those are there to fine the trucks for what they are carrying if it is beyond what is allowed among other things. You said km though so you probably are not in the US.
There's also tax built in to every gallon of fuel.
There are also flat annual registration fees you have to pay as well.
[1] https://www.insidescience.org/news/how-much-damage-do-heavy-...