Truck Radius

right now all trucks go all over the place.. you can't stop them. You need each truck to have a home point and a Max radius. This will stop them from going across the map with 5 units of sand

A mechanic like this would be useful when you want more flexibility than dedicated import/export routes, but still wish to somewhat constrain the movement of one or more trucks so they don't go haring off halfway across the map with each new job.
One example of this would be assigning a few trucks to my farming area; while no individual farm and possibly no individual storage merits having a dedicated truck, the area as a whole is going to have a reasonably consistent load, so assigning a handful of trucks to that area maximizes efficiency versus having a truck complete one crop delivery job, hare off to the opposite side of Curland to dump some slag from my quartz facility, and having a separate truck drive in from just completing a construction job at the far tip of the island to complete the next job.