What is one of the key rules when driving on a freeway?

Adhering to minimum speeds on a freeway is crucial for maintaining a smooth flow of traffic and ensuring safety for all drivers. Freeways are designed for higher-speed travel, and if a vehicle operates below the minimum speed limit, it can create dangerous situations, such as congestion or accidents, as faster-moving vehicles may need to change lanes abruptly to avoid the slower vehicle. This rule helps to keep traffic flowing efficiently, minimizing the risks of collisions and ensuring that drivers can anticipate the speed of vehicles around them.

In contrast, the other options are not standard practices on freeways. Stopping without warning can lead to serious accidents, as it disrupts the flow of traffic and creates hazards for other drivers. Driving in any lane disregards the regulations that designate specific lanes for slower or faster traffic, which can lead to confusion and congestion. Lastly, speed limits are enforced for safety reasons; ignoring speed limits can result in fines and increase the likelihood of accidents.