Final answer:
The maximum speed limit on all state routes or through highways where the speed limit is not posted is typically 55 mph.
Step-by-step explanation:
In the United States, the maximum speed limit on state routes or through highways where the speed limit is not posted is typically 55 miles per hour (mph). This is the answer to option 4. Some states may have different speed limits, so it's important to check the specific laws of the state you are in.