But compared to a lot of other states in the U.S., there aren’t very many cars in Iowa. That’s not to say that you won’t experience any traffic, though.
Roads near large cities like Des Moines tend to be a lot busier, and things like road construction can cause traffic jams even if there aren’t a lot of other vehicles on the road.
If you’re really concerned about traffic, one way to avoid the worst of it is to drive at night. By doing this, you’ll avoid any daytime commuters going to or from work. Instead, you’ll mostly be driving by semi-trucks and other commercial vehicles.