1、Designation: E 1710 05Standard Test Method forMeasurement of Retroreflective Pavement Marking Materialswith CEN-Prescribed Geometry Using a PortableRetroreflectometer1This standard is issued under the fixed designation E 1710; the number immediately following the designation indicates the year ofori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers measurement of the retroreflec-tive p
3、roperties of horizontal pavement marking materialscontaining retroreflecting beads, such as traffic stripes andsurface symbols, using a portable retroreflectometer that can beplaced on the road delineation to measure the retroreflection ata prescribed geometry.NOTE 1The restriction to bead based mat
4、erials is for the purpose ofensuring a sufficiently gradual optical response function (from points ofthe source aperture to points of the receiver aperture) to allow generoussized instrument source and receiver apertures.1.2 The entrance and observation angles of the retroreflec-tometer affect the r
5、eadings. As specified by the EuropeanCommittee for Standardization (CEN), the entrance and obser-vation angles shall be 88.76 and 1.05, respectively.1.3 This test method is intended to be used for fieldmeasurement of pavement markings but may be used tomeasure the performance of materials on sample
6、panels beforeplacing the marking material in the field.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility
7、 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4061 Test Method for Retroreflectance of HorizontalCoatingsD 6359 Specification for Minimum Retroreflectance ofNewly Applied Pavement Marking Using Portable Hand-Operated InstrumentsE 284 Terminology of Appearance2E
8、 809 Practice for Measuring Photometric Characteristicsof Retroreflectors22.2 Other Standard:CEN EN 1436 Road Marking MaterialsRoad MarkingPerformance for Road Users33. Terminology3.1 The terminology used in this test method generallyagrees with that used in Terminology E 284.3.2 DefinitionsThe deli
9、miting phrase “in retroreflection”applies to each of the following definitions when used outsidethe context of this or other retroreflection test methods:3.2.1 coeffcient of retroreflected luminance, RL, nthe ratioof the luminance, L, of a projected surface to the normalilluminance, E, at the surfac
10、e on a plane normal to theincident light, expressed in candelas per square metre per lux(cdm2lx1).3.2.1.1 DiscussionBecause of the low luminance of pave-ment markings, the units used commonly are millicandelas persquare metre per lux (mcdm2lx1).3.2.2 co-entrance angle, bC, nthe complement of theentr
11、ance angle (90 b).3.2.3 co-viewing angle, nC, nthe complement of theviewing angle (90 n).3.2.4 entrance angle, b, nthe angle between the illumi-nation axis and the retroreflector axis.3.2.5 observation angle, a, nthe angle between the illu-mination axis and the observation axis.3.2.6 portable retror
12、eflectometer, na hand-held instru-ment that can be used in the field or laboratory for measure-ment of retroreflectance.3.2.6.1 DiscussionIn this test method, “portable retrore-flectometer” refers to a hand-held instrument that can be placedover roadway delineation to measure the coefficient of retr
13、ore-flected luminance with a prescribed geometry.3.2.7 presentation angle, g, nthe angle between the ob-servation half-plane and the half-plane that originates on theillumination axis and that contains the retroreflector axis.1This test method is under the jurisdiction of ASTM Committee E12 on Color
14、and Appearance and is the direct responsibility of Subcommittee E12.10 onRetroreflection.Current edition approved Jan. 1, 2005. Published January 2005. Originallyapproved in 1995. Last previous edition approved in 1997 as E 1710 97.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from European Committee for Standardization, Central Secretariat(CEN), rue de Stassart 36, B1050 Brussels, Belgium.1Co
16、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.8 instrument standard, nworking standard used tostandardize the portable retroreflectometer.3.2.9 retroreflection, na reflection in which the reflectedrays are returned preferentially
17、in directions close to theopposite of the direction of the incident rays, this propertybeing maintained over wide variations of the direction of theincident rays.3.2.10 viewing angle, nthe angle between the retroreflec-tor axis and the observation axis.3.2.10.1 DiscussionThe retroreflector axis for
18、pavementmarkings is normal to the marking.4. Summary of Test Method4.1 This test method involves the use of commercial por-table retroreflectometers for determining the coefficient ofretroreflected luminance of horizontal coating materials used inpavement markings.4.2 The entrance angle is fixed at
19、88.76 (co-entrance angle1.24).4.3 The observation angle is fixed at 1.05.4.4 The presentation angle shall be 0.4.5 The portable retroreflectometers use either a built-inreference white for standardization or use an external panel ofknown coefficient of retroreflected luminance, or both.4.6 The retro
20、reflectometer is placed directly over the pave-ment marking to be measured, ensuring that the measurementarea of the retroreflectometer fits within the width of the stripe,and the reading displayed by the retroreflectometer is recorded.4.7 The retroreflectometer is then moved to other positionson th
21、e pavement marking, and the readings are recorded andaveraged.4.8 Readings shall be taken and averaged in each directionof traffic for a centerline.5. Significance and Use5.1 The quality of the stripe is determined by the coefficientof retroreflected luminance, RL, and depends on the materialsused,
22、age, and wear pattern. These conditions shall be observedand noted by the user.5.2 Under the same conditions of illumination and viewing,larger values of RLcorrespond to higher levels of visualperformance.5.3 Retroreflectivity of pavement (road) markings degradewith traffic wear and require periodic
23、 measurement to ensurethat sufficient line visibility is provided to drivers.5.4 For a given viewing distance, measurements of RLmadewith a retroreflectometer having a geometry corresponding tothat viewing distance are a good indicator of the visual rankingof material measured.5.5 As specified by CE
24、N, the measurement geometry of theinstrument is based on a viewing distance of 30 m, a headlightmounting height of 0.65 m directly over the stripe, and an eyeheight of 1.2 m directly over the stripe.5.6 It shall be the responsibility of the user to employ aninstrument having the specified observatio
25、n and entranceangles.6. Apparatus6.1 Portable Retroreflectometer:6.1.1 The retroreflectometer shall be portable, with thecapability of being placed on various horizontal pavementmarkings in different locations.6.1.2 The retroreflectometer shall be constructed so thatplacement on the highway pavement
26、 markings will precludeany stray light from entering the measurement area of theinstrument and affecting the reading.6.1.3 For the convenience of the user, a marking shall beplaced on the instrument to permit it to be aligned with thedirection of traffic.6.2 Light Source Requirements:6.2.1 The proje
27、ction optics shall be such that the distribu-tion of the illuminance over the measurement area will bewithin 10 % of the average illuminance.6.2.2 The aperture angle of the light source as determinedfrom the center of the measurement area shall not be largerthan a rectangle subtending 10 min of arc
28、(0.17) by 20 min ofarc (0.33).6.2.2.1 Rectangle aperture dimensions are given with thefirst side parallel to the observation half plane.NOTE 2The maximum source aperture dimensions are in agreementwith CEN EN 1436. There is experimental evidence that for this testmethod, using this maximum source ap
29、erture together with the maximumreceiver aperture in 6.3.3 produces RLmeasurements within 1.5 % of thoseusing two 10-min circular apertures as specified in Test Method D 4061.6.3 Receiver Requirements:6.3.1 The receiver shall have sufficient sensitivity and rangeto accommodate coefficient of retrore
30、flected luminance valuesexpected in use, typically 1 to 2000 mcdm2lx1.6.3.2 The combined spectral distribution of the light sourceand the spectral responsivity of the receiver shall match thecombined spectral distribution of CIE Standard Illuminant Aand the V(l) spectral luminous efficacy function.
31、The matchshall ensure correct measurement of at least white and yellowpavement marking materials according to the following crite-rion:6.3.2.1 A white (spectrally neutral) reflection standard andtwo plano parallel long pass absorption filters with passwavelengths at respectively approximately 515 nm
32、 and 550nm, providing colors of yellow and amber, are used.6.3.2.2 The white reflection standard is measured. An ab-sorption filter is inserted in front of the white reflectionstandard, so that illumination and measurement takes placethrough the filter, and a new measurement is made. The filtershall
33、 be mounted with a small tilt to avoid signal by surfacereflection, and at some distance from the standard to avoidsurface reflection back to the standard. See Fig. 1.FIG. 1 White Reflection Standard and Absorption Filter forTesting Spectral MatchE17100526.3.2.3 The ratio of the RLmeasured with a fi
34、lter to the RLmeasured without the filter shall be within 5 % of the Illumi-nant A luminous transmittance of an air-spaced pair of twosuch filters.6.3.2.4 Filters of colors other than described above may beused to demonstrate the ability of a retroreflectometer tomeasure pavement marking materials o
35、f such colors. A longpass absorption filter with a pass wavelength at approximately715 nm corresponding to infrared may also be used. The RLwith the infrared filter inserted is theoretically zero, but ameasured RLup to 5 % of the RLof the white standard may beacceptable.6.3.3 The aperture of the rec
36、eiver as determined from thecenter of the measurement area shall not be larger than a squaresubtending 20 min of arc (0.33) by 20 min of arc (0.33).NOTE 3The maximum receiver aperture dimensions are in agreementwith CEN EN 1436. There is experimental evidence that for this testmethod, using this max
37、imum receiver aperture together with the maxi-mum source aperture in 6.2.2 produces RLmeasurements within 1.5 % ofthose using two 10-min circular apertures as specified in Test MethodD 4061.6.3.4 Instruments with annular apertures are not recom-mended for measuring pavement markings.6.3.5 The combin
38、ed stability of the output of the lightsource and receiver shall be such that readings will not changemore than 6 1 % after 10 s when the retroreflectometer is incontact with the pavement marking and ready to measure.6.3.6 The linearity of the retroreflectometer photometricscale over the range of re
39、adings expected shall be within 2 %.Correction factors may be used to ensure a linear response. Amethod for determining linearity is found in Annex A2,Method for Determining Photoreceptor Linearity, of PracticeE 809.6.4 Measurement Geometry:6.4.1 The light source and receiver may be either at optica
40、linfinity or at a finite distance from the measurement area, andthey shall be separated from each other by a distance corre-sponding to an observation angle of 1.05 6 0.02.6.4.2 The entrance angle of the retroreflectometer shall be88.76 6 0.02 with respect to the entrance aperture plane.6.4.3 The pr
41、esentation angle of the retroreflectometer shallbe 0 and shall be stated in the instrument specifications.6.4.4 See Fig. 2 for a diagram of the optics geometry.6.4.5 The length of the detected area shall either be fullyincluded within the length of the illuminated area (called“arrangement A”) or the
42、 length of the illuminated area shall befully included within the length of the detected area (calledarrangement B”).NOTE 4Arrangement B is advantageous to arrangementAin the sensethat it leads to less variation of the measured RLvalue with small tilts ofthe retroreflectometer that are unavoidable i
43、n practical field measure-ments.6.4.6 The smaller of the two areas, detected or illuminatedarea, is the measurement area and shall be at least 50 cm2. SeeFig. 3 for a method of testing this area.NOTE 5The plate mentioned in Fig. 3 needs in most cases to be aglass plate with a diffuse upper surface,
44、so that the area can be studiedfrom the underside.6.4.7 Retroreflectometers can be characterized as “fixed-aim instruments” or “aiming instruments.” A fixed-aim instru-ment has no facility for adjustment of its tilt once it is placedon the pavement marking, while an aiming instrument has aFIG. 2a An
45、gles and apertures for non-collimating portableretroreflectometerFIG. 2b Angles and apertures for collimating optics portableretroreflectometerFIG. 2c Angles and apertures for portable retroreflectometerwith collimating and beam splitter designFIG. 2 Optics Geometry Diagram for Portable Road Marking
46、Reflectometer: a) Angles and Apertures for Non-CollimatingPortable Reflectometer; b) Angles and Apertures for CollimatingOptics Portable Reflectometer; c) Angles and Apertures forPortable Reflectometer with Collimating and Beam SplitterDesignNOTE 1The double brightness area is the measurement area.
47、Its lengthis measured from middle of blur to middle of blur.FIG. 3 With an Auxiliary Light Through the Detector ApertureStop, the Detected and Illuminated Areas are Projected onto aPlate in the Ground PlaneE1710053facility for adjustment of its tilt and some facility for indicationof the consequent
48、position of the measurement area defined in6.4.6.6.4.7.1 For fixed-aim instruments, the height tolerance shallbe verified to extend from 1 mm to +2 mm by the followingtest: RLvalues measured on a panel shall vary at most 6 10 %,when the height position between panel surface and retrore-flectometer H
49、 is changed from 0 mm to 1 mmm, 1 mm or 2mm. The RLvalues measured on a panel when height position(H) between panel surface and the instruments normal mark-ing plane is either 1 mm, +1 mm, or +2 mm shall all bebetween 0.93 and 1.13 the RLvalue measured when H iszero. See Fig. 4 for a method of testing the variation.NOTE 6Depth tolerance requires that the larger of the two areas,detected or illuminated area, has sufficient reserve and spatially uniformcharacteristics (either illumination or sensitivity). This is illustrat
