To enforce work zone speed limits effectively, what must be present?

• A. Only a sign
• B. A posted sign with flashing lights
• C. Workers must be present
• D. B and C only

Answer: (D)

To enforce work zone speed limits effectively, a combination of a posted sign with flashing lights and the presence of workers is essential. The posted sign serves as a critical reminder to drivers that they are entering a work zone where special speed limits apply, while flashing lights enhance visibility and urgency, drawing more attention to the sign. This signals to drivers that caution is needed, as conditions may change swiftly in a work zone.

Additionally, having workers present not only reinforces the presence of a work zone but also emphasizes the potential risks that may affect traffic flow and safety. The presence of workers indicates active work being done, which can often lead to unexpected hazards. Consequently, signs paired with the visibility of workers help to significantly increase compliance with speed limits and maintain safety for both drivers and workers alike.

The other choices do not encompass the necessary elements for effective enforcement in such scenarios. A sign alone, even with flashing lights, may not adequately convey the need for reduced speed, especially if no visible human presence reinforces that caution must be exercised. Thus, the correct approach requires both elements for optimal effectiveness in enforcing work zone speed limits.