What type of light would be appropriate for guiding vehicles on service roads?

Amber lights are commonly used for guiding vehicles on service roads due to their visibility and the safe warning they provide. Amber lights serve as a cautionary signal, alerting drivers to potential hazards or changes in driving conditions without implying a stop requirement, which is essential for areas where traffic needs to flow smoothly. This color helps ensure that drivers remain cautious while navigating these areas, promoting safety and awareness.

In contrast, red lights typically indicate a stop or an immediate hazard, making them unsuitable for a guiding function on service roads. Green lights often signify go or follow, which may not be appropriate for service road conditions that require heightened awareness. Blue lights, while associated with emergency services, can confuse drivers in non-emergency situations. Therefore, the use of amber lights is advantageous as they effectively communicate important guidance while maintaining necessary caution on service roads.