The chromaticity of the stripe is determined by means of the tristimulus values X, Y and Z for the CIE 1931 (2°) standard observer for CIE standard illuminant A, which are converted to the chromaticity coordinates (x, y) and shown in the CIE 1931 (x, y)-chromaticity diagram. Refer to Practice E 308.

Under the same conditions of illumination and viewing, the chromaticity coordinates (x, y) represent the nighttime color of pavement markings in vehicle headlamp illumination as seen by drivers of the vehicles.

The chromaticity of pavement (road) markings may change with traffic wear and require periodic measurement to ensure that the chromaticity is maintained within boundaries (see Specification D 6628 for examples of color boundaries).

As specified by CEN EN 1436 and Test Method E 1710, the measurement geometry of the instrument is based on a viewing distance of 30 m, a headlamp mounting height of 0.65 m and an eye height of 1.2 m.

It shall be the responsibility of the user to employ an instrument having the specified observation and entrance angles.

1.1 This test method covers measurement of the nighttime chromaticity coordinates (x, y) of horizontal pavement markings, such as traffic stripes and surface symbols, using a portable retroreflection colorimeter that can be placed on the road delineation to measure the chromaticity at a prescribed geometry.

1.2 The entrance and observation angles of the retrorecolorimeter affect the readings. As specified by the European Committee for Standardization (CEN EN 1436), the entrance and observation angles shall be 88.76 and 1.05, respectively.

1.3 This test method is intended to be used for field measurement of pavement markings but may be used to measure the chromaticity of materials on sample panels before placing the marking material in the field.

1.4 The portable retroreflection colorimeter may integrate measurement of the coefficient of retroreflected luminance RL according to Test Method E 1710 and thus be an integrated retroreflectometer/retroreflection colorimeter.

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.