Final answer:
Reduced construction zone speed limits apply at all times when construction is taking place, and are enforced even when workers are not present. These limits are posted on signs near the zones, and higher fines may apply for speeding.
Step-by-step explanation:
Reduced construction zone speed limits apply whenever construction is taking place whether workers are present or not. The de jure (legally enacted) speed limit is usually clearly posted on signs near the construction zone. However, the de facto (practically enforced) speed limit may vary based on enforcement discretion, though it is always safest and legally advisable to follow the posted speeds.
When you approach a construction zone, it is crucial to reduce your speed according to these lowered speed limits to ensure the safety of the workers as well as other motorists. Many jurisdictions impose higher fines for speeding in these zones, and traffic enforcement is often heightened to ensure compliance. Always be aware of the fluctuating traffic patterns and slower speeds required when navigating through construction zones.