ASTM E1696-15(2022)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1696 −15 (Reapproved 2022)
Standard Test Method for
Field Measurement of Raised Retroreflective Pavement
Markers Using a Portable Retroreflectometer
This standard is issued under the fixed designation E1696; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers the measurement of the retrore- 2.1 ASTM Standards:
flectivepropertiesofraisedretroreflectivepavementmarkersat E284Terminology of Appearance
a prescribed geometry, by means of a portable retroreflecto- E808Practice for Describing Retroreflection
meter that can be used in the field. The measurements can be E809Practice for Measuring Photometric Characteristics of
compared to minimum requirements to determine the need for Retroreflectors
replacement.
3. Terminology
1.2 The observation angle specified for retroreflectometers
3.1 The terms and definitions in Terminology E284 are
in this test method is that currently specified for raised
applicable to this test method. Some terms particular to
pavementmarkersintheUnitedStatesandmaydifferfromthe
retroreflection are defined and illustrated in Practice E808.
angles used elsewhere. For other jurisdictions, replace the
observations angle specified herein with the observation angle
3.2 Definitions:
specified by the pertinent agency. 3.2.1 The delimiting phrase “in retroreflection” applies to
eachofthefollowingdefinitionswhenusedoutsidethecontext
1.3 This test method is intended to be used for field
of this or other retroreflection standards.
measurement of raised retroreflective pavement markers but
3.2.2 coeffıcient of luminous intensity, R , n—of a
I
may also be used to measure the performance of new markers
retroreflector, ratio of the luminous intensity (I) of the retrore-
before they are placed in the field.
flector in the direction of observation to the illuminance (E|nt)
1.4 This test method covers measurements of raised pave-
at the retroreflector on a plane perpendicular to the direction of
−1
ment markers mounted on a road surface or mounted in
incident light, expressed in candelas per lux (cd·lx ).
snow-plowable metal castings.
3.2.2.1 Discussion—When values are low, the coefficient of
1.5 The values stated in SI units are to be regarded as the (retroreflected) luminous intensity may be given in millican-
−1
standard. The values given in parentheses are for information delas per lux (mcd·lx ). R =(I/E|nt).
I
only.
3.2.3 instrument standard, n—a working standard used to
1.6 This standard does not purport to address all of the standardize the portable retroreflectometer.
safety concerns, if any, associated with its use. It is the
3.2.4 portable retroreflectometer—a hand-held instrument
responsibility of the user of this standard to establish appro-
that can be used in the field or in the laboratory for measure-
priate safety, health, and environmental practices and deter-
ment of retroreflectance.
mine the applicability of regulatory limitations prior to use.
3.2.4.1 Discussion—In this test method, “portable retrore-
1.7 This international standard was developed in accor-
flectometer”referstoahand-heldinstrumentthatcanbeplaced
dance with internationally recognized principles on standard-
over a raised retroreflective pavement marker to measure the
ization established in the Decision on Principles for the
coefficient of luminous intensity with a prescribed geometry.
Development of International Standards, Guides and Recom-
4. Summary of Test Method
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.1 This test method involves the use of commercial por-
table retroreflectometers for determining the coefficient of
luminous intensity of pavement markers.
This test method is under the jurisdiction of ASTM Committee E12 on Color
and Appearance and is the direct responsibility of Subcommittee E12.10 on
Retroreflection. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2022. Published November 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1995. Last previous edition approved in 2015 as E1696–15. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E1696-15R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1696 − 15 (2022)
4.2 Entrance angle component β shall be between −2° and raised retroreflective pavement markers at distances of ap-
0°; entrance angle component β shall be 0° 6 2°. proximately 220 m (720 ft) for cars or approximately 440 m
(1440ft)fortruckswhenilluminatedbytungstenfilamentlight
4.3 Unless otherwise specified by the user, the observation
sources such as car headlights.
angle shall be 0.2° 6 0.01°.
5.2 There are some castings that block vehicle illumination
4.4 The observation half plane shall be vertical. Rotation
of a portion of the marker mounted within it. In this case,
angle shall be 0° (see Fig. 1 and Fig. 2).
measured R can be significantly lower than when the marker
I
4.5 The aperture angles of the source and of the receiver
is photometered outside the casting, but will correspond to the
shalleachbe0.1°withatoleranceof 60.04°onthesumofthe
visual observation.
two aperture angles.
5.3 The test method is not applicable to raised pavement
4.6 The aperture angle of an individual retroreflective ele-
markers mounted in depressions cut into the pavement.
ment shall be 0.02° max (see Practice E809). For a portable
5.4 The coefficient of luminous intensity of raised retrore-
photometer this aperture angle can be achieved by interposing
flective pavement markers degrades with traffic wear and
a collimating lens in the illumination and observation axes.
requires periodic measurement to ensure that sufficient visibil-
4.7 A portable standard shall be used for standardization.
ity is provided to the driver.
4.8 After standardization place the retroreflectometer di-
5.5 The quality of the pavement markers as to materials
rectly over the marker to be tested making sure that the
used, age and wear pattern, will have an effect on the
road-axis marking on the retroreflectometer is parallel to the
coefficient of (retroreflected) luminous intensity. These condi-
lane line of the road.
tions need to be observed and noted by the user.
4.9 The reading displayed by the retroreflectometer is re-
corded. The retroreflectometer is removed from the marker,
6. Apparatus
then replaced and the reading recorded again. If the difference
6.1 Portable Retroreflectometer:
in readings is greater than 10%, the process is to be repeated
6.1.1 The retroreflectometer shall be portable with the
a third time.
capability of being positioned over markers installed on the
roadway surface.
5. Significance and Use
6.1.2 The retroreflectometer shall be constructed so that
5.1 Measurements of R made by this test method, with the
I
placement on the road will preclude any stray light from
0.2° observation angle, are related to visual observation of
entering the area being tested under daylight conditions.
6.1.3 The retroreflectometer shall be constructed so that it
can be placed over the marker with the illumination axis
approximately parallel to the road surface.
6.1.4 The combined spectral distribution of the light source
and the spectral responsivity of the receiver shall match the
combined spectral distribution of CIE Standard Illuminant A
and the V(λ) photopic spectral luminous efficacy function
according to the following two criteria for all λ between
470nm and 640nm:
830 2 830
λ 2 λ
exp S λ R λ A λ V λ
SS D D ~ ! ~ ! ~ ! ~ !
( (
λ5360 λ5360
0.9, ,1.1
830 830
λ 2 λ
1 2
exp A λ V λ S λ R λ
SS D D ~ ! ~ ! ~ ! ~ !
( (
λ5360 λ5360
and also
S λ R λ
~ ! ~ !
(
λ5670
,0.02
1 2
S λ R λ
~ ! ~ !
(
λ5360
where:
S(λ) = instrument illumination spectral power distribution,
R(λ) = instrument spectral responsivity,
A(λ) = CIE Standard Illuminant A, and
V(λ) = CIE photopic luminous efficacy function.
The λ shall be chosen at 5 nm intervals and the summations
shall be
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