Final answer:
When speed limits are not posted on one or two lane ordinary roads, they're typically determined by state or local laws and can range generally from 25 to 55 mph. Understanding the difference between legally posted (de jure) and effectively enforced (de facto) speed limits is pivotal for compliance.
Step-by-step explanation:
The speed limits on roadways serve to regulate traffic flow and ensure safety. When speed limits are not clearly posted on one or two lane ordinary roads, the default limit is typically set by state or local laws. These default speed limits may vary but often fall within a common range of 25 to 55 miles per hour.
De jure vs. De facto Speed Limits
It's important to understand the distinction between de jure (legal) speed limits and de facto speed limits. The de jure speed limit is the legally posted limit, as indicated on road signs. In contrast, the de facto speed limit refers to the speed at which you are likely to get pulled over by the police. This may vary due to enforcement policies or conditions on the road.