According to NFPA ambulance retroreflective strips requirements, what should be the configuration of chevrons?

The configuration of chevrons on ambulances, as specified by the National Fire Protection Association (NFPA) standards, requires the use of a single color alternating between red and yellow. This color scheme is designed to enhance visibility and recognition of emergency vehicles, particularly in low light conditions or inclement weather.

The red and yellow combination is effective for alerting the public and other drivers to the presence of an emergency vehicle, providing a clear and distinct pattern that is widely recognized. The bright contrast between the red and yellow enhances the reflectivity of the strips, making them more noticeable and improving safety during nighttime or foggy conditions.

Other color combinations listed do not meet the NFPA's criteria for ambulance marking. For instance, blue and green or neon green do not have the same level of recognition and may not provide the necessary visibility required for emergency response situations. Therefore, the use of red and yellow not only adheres to the NFPA guidelines but also maximizes safety on the road.