Why factories don't order ahead and from nearest supplier?
I have constant troubles with factories in this game. I've set up only one factory and it lacks resources most of the time.
I did set up every storage building on fill so it doesn't export outside of the city, but it doesn't help. I have usage of trucks between 0 and 3 for storage buildings.
As an experiment I cut off access to the rest of the world and it worked perfectly – just before factory ran out of supplies, there was delivery and I newer saw any problem with resources.
Best Answer
I think your question might be answered by this link. It is a more complex answer, but might be worth reading. What seems very important is to have raw and processed storage spaces, short travel routes for the industry trucks and also intersections, or U-turns nearby facilities. Also, storage filling is also tricky, while for example a storage building set to fill might import all it's resources. This, and other aspects are addressed in the above link, in more detail.