What is required in order for a tubular marker to function properly at night?

For a tubular marker to function properly at night, it must be retroreflective. This characteristic allows the marker to reflect light back to the source, such as headlights from vehicles. When a driver approaches a retroreflective marker at night, the light from their vehicle's headlights strikes the marker and is redirected back towards the vehicle, making the marker highly visible.

This retroreflective feature enhances safety by ensuring that the markers can be clearly seen under low-light conditions, which is crucial for guiding drivers safely through work zones or along roadways. In contrast, while fluorescent markers may be visible during the day, they do not provide the same visibility in darkness. Reflective markers typically refer to those that reflect light but may not redirect it back as effectively. Matte finishes would not aid in visibility at night, as they do not reflect light in a way that enhances visibility.