The state has long has the ability to “close” the interstate. Normally, this just implies that the weather makes any travel dangerous and if you go out and get stuck you’ll be fined heavily for going out after you’ve been warned.
Recently several gates have been installed on on-ramps in the Siouxland area which can be closed to physically bar access to the Interstate.
Those who would go out when the Interstate is closed will still go out if the gates are closed. However, now they are forced to take secondary roads which are arguably more dangerous than the interstate in adverse weather due to narrowness of the lanes, and that two-way traffic is mixed on the same road.
On the interstate, when you’re alone, you can putz along in the middle of two lanes going slow and you have nearly 20 feet of road on either side of you.
I don’t agree that installing gates is a solution.