Semi truckand and distribution centers

add in the tier three solid trucks as semis semis should only drive on flat ground. Add a building called the distribution center. Make it function sort of like the shipyard. It should have a huge footprint, and a large amount of mixed storage for flat items, that can only be picked up by semis in front, and added/distributed by belt in the back. Semis should only pick up and move items from distribution centers, and only if a import/export route is set up with a truck assigned. Tier 3 loose(haul) trucks should only be able to be loaded by excavators, and only able to dump on the ground, or sorting facilities.

This will give a much more complex endgame. Now you have to plan routes and dig flat ground to drive trucks, you have a reason to learn and interact with the import/export and priority systems, a reason to use belt sorters and convayer dumps, you have to plan fleets more carefully.