ASTM E2177-20 PDF Download

ASTM E2177-20 is a standard test method that outlines the procedure for measuring the coefficient of retroreflected luminance (RL) of pavement markings using the Bucket Method in a condition of wet recovery. This method is applicable to horizontal pavement marking materials such as traffic stripes and road surface symbols.

The standard emphasizes the importance of understanding the nighttime performance of pavement markings, which is determined by the coefficient of retroreflected luminance. It is noted that this performance depends on factors such as the materials used, age, and wear pattern of the markings. The larger values of RL correspond to higher levels of visual performance at corresponding geometry under the same conditions of headlight illumination and driver's viewing.

The test method specifically focuses on the measurement of the wet retroreflective properties of pavement markings in a condition of wet recovery. This condition typically occurs after a rainfall has ended or when the markings are wet from dew or humidity. It is important to note that the results obtained from this test method may not necessarily reflect the performance of the markings in conditions of rain while being rained upon.

The standard also specifies the use of portable reflectometers that comply with Test Method E1710. These reflectometers should have the specified observation and entrance angles, commonly referred to as "30 meter geometry". The retroreflectivity of the pavement markings is measured at the prescribed geometry to assess their performance and visibility to drivers.