1.1 This test method covers the measurement of the wet retroreflective (R_L) properties of horizontal pavement marking materials, such as traffic stripes and road surface symbols, using a portable or mobile retroreflectometer that can be placed on or before the road marking to measure the retroreflection at the prescribed geometry.

1.2 This method of measuring the wet retroreflective properties (R_L) of pavement markings measures the wet retroreflectivity in a standard condition of wetness (see Fig 1).

1.2.1 Discussion—This test condition typically exists (1) after a rainfall has ended and the pavement markings are still wet or (2) as the markings are wet from dew or humidity.

1.3 Retroreflective performance obtained with this test in conditions of wetness does not necessarily relate to how markings perform in conditions of rain, that is, as markings are being rained upon.

Note 1—Test Method E 2176 defines a method to use to measure the performance of pavement markings in conditions of simulated rain.

1.4 This test method specifies the use of portable or mobile reflectometers that can measure pavement markings in accordance with Test Method E 1710. The entrance and observation angles required of the retroreflectometer in this test method are commonly referred to as "30 meter geometry."

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.