If you want to get to your destination quickly and don't mind paying the toll in expressway, then expressway is a good choice. Through expressway, you can avoid traffic lights and traffic jams and save time. From Loudi to Xiangtan Institute of Technology, you can choose G4 Beijing-Hong Kong-Macao Expressway or G4W3 Loudi Ring Expressway, and then transfer to G 106 National Highway.
On the other hand, if you want to enjoy the scenery along the way, or don't want to pay the toll in expressway, then taking the national highway is a good choice. Although there may be traffic jams and traffic lights on the national highway, you can choose a more free way to travel. You can choose places along the way to stop and rest or visit some scenic spots. If you choose to take the national highway, you can choose G 106 national highway to go directly to Xiangtan Institute of Technology.
In a word, choosing expressway or National Highway depends on personal travel needs and preferences.