Bret is absolutely correct about the two ways to pay drivers. Something that should be pointed out is that with the "driver pays fuel and tolls" scenario, you put the responsibility and expense for idling onto the drivers.
Something that i have never agreed with is the splitting of certain other revenue, such as driver load / unload pay (the driver did ALL the work), and, in the case of your drivers paying for fuel, any fuel surcharges, deadhead or empty move pay, since these monies are meant to offset the cost of the fuel used when doing them.
On the other hand, it's YOUR business equipment that is being kept idle, so i agree with a split for detention and layover pay. Pickup and Delivery are normal parts of the job, and the revenue for them should be split, also.
Best of luck to you and your wife!
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Godspeed to all of you out there on the highways and byways!