Rates pay more West to East and North to South

Why does this happen? Not sure but really does.  Brokers pay top dollar to ship from NJ to TX and huge discounted rates to go back the other way.  I guess some has to do with the south has less manufacturing. West has more produce and imports. Chicago has imports.

Density and less trucks plays a part.  More trucks then freight plays a big part.

I guess that is why load boards are heavy on freight from North East. No need to post a load from CA to NY because brokers have their go to carriers all ready set up.