Factors Affecting Night-Time Visibility of Retroreflective Road Traffic Signs: A Review

Abstract

Road traffic signs define a visual language that can be interpreted by drivers. They represent the current traffic situation on the road, show danger and difficulties around the drivers, give them warnings, and help them with their navigation by providing useful information that makes driving safe and convenient. The main part of the road traffic sign is the retroreflective material which reflects the light from the vehicle headlights to the driver. Driving during night-time is a challenge, and the rertoreflective material on the sign board helps the drivers to perceive and interpret the information on the road traffic sign properly. The aim of this paper is to study the factors affecting the performance of driving during nighttime and the role the retroreflective material that plays in this regard. The vehicle headlights, ambient conditions, and the type of retroreflection material affect the light reflected from the road traffic signs. It is also found that the retroreflectivity depends on vehicle factors such as headlights colour and angle of illumination. Other factors such as environmental factors and sign factors can also affect the retroreflectivity.

Improving Autonomous Vehicle Perception through Evaluating LiDAR Capabilities and Handheld Retroreflectivity Assessments

“…However, assessing retroreflectivity and chromatic characteristics in road traffic signs is a complex task, as there is no definitive threshold for determining operational obsolescence. This challenge has been observed in studies conducted in Sweden [ 10 ] and Hungary. In a separate study, ref.…”