I'd like to help the volunteers and staff where I work to be more reliable at turning in receipts for gasoline purchases after they "fill the tank" when they"ve been on the road transporting people/hauling donated food and produce, instead of taking them home.

The number of receipts turned in is usually well under the actual amount of charges that have been transacted each month.

This obviously cuts into the productivity of the controller as she tries to recoup the receipts.

Can GTD be implemented to help the drivers to be more reliable and solve this kind of issue and if so, does anyone have any "nuts and bolts" suggestions?