jr46812000 is correct guys and gals. Typically it is calculated by the truck needed and the weight/dims of the load times the mileage.
The default rates we have in place for customers are typically the high paying ones to your vehicles. The problem occurs when there is more than one company trying to get the business from that customer. ABC company goes in and offers $1/mile and XYZ company goes in and offers .90/mile and so on and so forth which in-turn drives the price down and pays less.
The top dollar per mile continues to increase yet the loads paying that much are sometimes few are far between because the customer has another company willing to do the load for less money.
So what do we do? Say too bad and wait for the next load or drop our price for that customer and be happy that we got the load and are atleast making some money?
It is a cut-throat industry where price and service is everything. Our B-Unit (cargo van) contractors are paid anywhere between .50/mile up to $1.10/mile. The average for cargo van with Bolt for the year is roughly .80/loaded mile which may not pay the highest in the Industry yet we get the miles because of our pricing to the customer.