Does a posted speed limit of 55 mph mean that you may drive 55 mph on that highway under all conditions?

The posted limit is the maximum speed allowed under the best possible conditions. If a road is wet, icy, or otherwise impeded by lack of visibility or other obstructions, it is necessary to drive more slowly to match the conditions and maintain an appropriate level of safety.

Drivers must also be aware of additional potential hazards such as sharp turns, wildlife crossings, debris in the road, the appearance and actions of other vehicles, and other possible risks. Drivers must be cautious and aware of their surroundings in order to adjust their speed when needed.