ASTM D7585/D7585M-10(2022)
(Practice)Standard Practice for Evaluating Retroreflective Pavement Markings Using Portable Hand-Operated Instruments
Standard Practice for Evaluating Retroreflective Pavement Markings Using Portable Hand-Operated Instruments
SIGNIFICANCE AND USE
5.1 This practice provides procedures for the determination of the retroreflective performance of pavement markings. This practice does not set the minimum retroreflectance values for pavement markings; it describes sampling criteria for determining the retroreflective properties of pavement markings, which then can be used to determine compliance with a specification. It is the responsibility of the agency having jurisdiction to set the acceptable retroreflectivity values within their own specifications.
5.2 This practice does not purport to address all the concerns regarding contamination of the markings, but the following may be helpful. It is very important that the markings being evaluated are clean and dry. If the evaluation is being used relative to a measure of the performance of a contractor, it is imperative that the parties agree beforehand on the definition of clean and dry. There are many forms of contamination on a roadway that will lower the retroreflectivity readings of a marking, but not all of them can be removed. Asphalt oil and rubber skid marks are examples. Loose dirt can be removed by pressure washing, perhaps using soap, brushing, or high-pressure air; however, these techniques are usually insufficient to remove dirt that is packed into the marking surface. Care should be taken to select areas that are typical of the marking section, avoiding areas of paint tracking or contamination, for example. It may be useful to take photographs using a digital camera and a good macro lens to be able to see the contamination on or between the glass beads.
SCOPE
1.1 This practice describes several field techniques to evaluate the retroreflective properties of pavement markings containing retroreflecting optics (for example, centerlines and edgelines) and applied to the road surface. The techniques described in this practice contain sampling criteria such as the length of test sections and the number of measurements needed. The practice is based on retroreflective measurements made with portable hand-operated instruments in compliance with Test Method E1710.
1.2 The data obtained from this practice can be used to determine the acceptance or rejection of a project based on specified levels of retroreflectivity established by the agency having jurisdiction.
1.3 This practice can be used for the evaluation of newly installed or existing pavement markings. When testing newly applied pavement markings, it is recommended that the evaluation be done no sooner than 48 h after application but before 30 days after application so that excess retroreflective optics, such as glass spheres, are no longer present.
1.4 The assessment techniques in this practice are based on best practices and designed to provide three levels of confidence in terms of quantifying the retroreflective performance of markings. Each technique represents a tradeoff between the number of measurements and the confidence of the retroreflective performance of the markings under study.
1.5 This practice can be used by agencies as is or may be customized to meet an agency’s specific needs. Where applicable, the practice describes areas where different assumptions could be made, which would impact the sampling needs and the confidence levels of the results. When deviations from this practice are made, they shall be documented in the test report.
Note 1: When measuring newly installed pavement markings, there are several factors that contribute to erroneous values for measurements made within a short time after application, such as excess retroreflective optics, top coatings on tape, incomplete curing of the binder, and coatings on the retroreflective optics. Retroreflective measurements taken within 48 h after application may be useful to quickly gauge the application quality but are not intended to be used with this practice.
Note 2: When measuring existing or in-service pavement markings, care should be ta...
General Information
- Status
- Published
- Publication Date
- 30-Apr-2022
- Technical Committee
- D04 - Road and Paving Materials
- Drafting Committee
- D04.38 - Highway Traffic Control Materials
Relations
- Effective Date
- 01-Dec-2023
- Effective Date
- 01-Oct-2018
- Effective Date
- 01-Jan-2018
- Effective Date
- 01-Jan-2016
- Effective Date
- 01-Nov-2013
- Effective Date
- 01-Jul-2013
- Effective Date
- 01-Jun-2013
- Effective Date
- 01-Jan-2013
- Effective Date
- 01-Jul-2012
- Effective Date
- 01-Jun-2011
- Effective Date
- 01-Jun-2009
- Effective Date
- 01-Feb-2009
- Effective Date
- 01-Jan-2009
- Effective Date
- 01-Aug-2008
- Effective Date
- 15-Jul-2007
Overview
ASTM D7585/D7585M-10(2022), developed by ASTM International, outlines standard practice for evaluating the retroreflective properties of pavement markings using portable, hand-operated instruments. This standard is critical in assessing road marking visibility and performance, as it offers practical procedures and sampling criteria for the field measurement of retroreflection. The standard is designed for both newly installed and existing pavement markings containing retroreflective optics-such as glass beads-used for traffic lines, centerlines, edgelines, and other road surface markings.
Agencies rely on ASTM D7585/D7585M-10(2022) to help determine compliance with their own road visibility and safety requirements. The standard does not establish minimum retroreflectivity values but provides a robust methodology to measure and document these properties in alignment with specific project or maintenance specifications.
Key Topics
- Retroreflective Measurement Procedures: The standard details sampling criteria, including section length and number of measurements, to ensure a representative assessment of pavement marking retroreflectivity.
- Protocols for Various Marking Types: Guidance includes methods for longitudinal markings (centerlines, edgelines), non-longitudinal markings (symbols, pedestrian crossings), and different project lengths.
- Hand-Operated Instrumentation: All measurements are performed using portable, hand-operated retroreflectometers, following calibration and best-use practices.
- Assessment Confidence Levels: Three distinct techniques are described-visual inspection, standard evaluation, and referee evaluation-each with a different balance of measurement frequency and statistical confidence.
- Contamination and Surface Conditions: The standard emphasizes the importance of clean and dry surfaces for accurate readings, detailing best practices for ensuring reliable results.
- Documentation and Reporting: Clear requirements exist for reporting test procedures, equipment calibration, environmental conditions, and any deviations from the standard practice.
Applications
ASTM D7585/D7585M-10(2022) is widely applicable in the following scenarios:
- Roadway Safety Compliance: Transportation agencies use this standard to evaluate the visibility of pavement markings, ensuring compliance with safety programs and nighttime driving requirements.
- Project Acceptance: Contractors and agencies leverage these procedures to determine if newly installed pavement markings meet specified performance thresholds prior to final acceptance.
- Routine Maintenance Monitoring: Routine evaluations of in-service pavement markings are conducted to monitor performance degradation and plan maintenance or replacement when retroreflectivity falls below acceptable levels.
- Field Quality Control: The standard’s guidance supports consistent, repeatable measurement procedures across projects and jurisdictions, facilitating effective quality control.
- Research and Product Evaluation: The standard can aid in assessing the field performance of new pavement marking materials or application processes by providing a reliable basis for comparison.
Related Standards
ASTM D7585/D7585M-10(2022) is connected to several other key ASTM and industry documents, including:
- ASTM E1710: Test Method for Measurement of Retroreflective Pavement Marking Materials with CEN-Prescribed Geometry Using a Portable Retroreflectometer
- ASTM E284: Terminology of Appearance
- ASTM E808: Practice for Describing Retroreflection
- ASTM D4061: Test Method for Retroreflectance of Horizontal Coatings
- ASTM D6359 (Withdrawn): Specification for Minimum Retroreflectance of Newly Applied Pavement Marking Using Portable Hand-Operated Instruments
Practical Value
Adopting ASTM D7585/D7585M-10(2022) ensures uniformity and repeatability in retroreflective pavement marking assessments across road safety and infrastructure projects. With clear guidelines for field measurements using portable retroreflectometers, the standard benefits road agencies, contractors, and materials suppliers aiming to optimize road visibility, enhance traffic safety, and demonstrate compliance with established specifications.
Keywords: ASTM D7585, retroreflective pavement markings, road marking visibility, portable retroreflectometer, pavement marking compliance, field assessment, highway safety.
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Frequently Asked Questions
ASTM D7585/D7585M-10(2022) is a standard published by ASTM International. Its full title is "Standard Practice for Evaluating Retroreflective Pavement Markings Using Portable Hand-Operated Instruments". This standard covers: SIGNIFICANCE AND USE 5.1 This practice provides procedures for the determination of the retroreflective performance of pavement markings. This practice does not set the minimum retroreflectance values for pavement markings; it describes sampling criteria for determining the retroreflective properties of pavement markings, which then can be used to determine compliance with a specification. It is the responsibility of the agency having jurisdiction to set the acceptable retroreflectivity values within their own specifications. 5.2 This practice does not purport to address all the concerns regarding contamination of the markings, but the following may be helpful. It is very important that the markings being evaluated are clean and dry. If the evaluation is being used relative to a measure of the performance of a contractor, it is imperative that the parties agree beforehand on the definition of clean and dry. There are many forms of contamination on a roadway that will lower the retroreflectivity readings of a marking, but not all of them can be removed. Asphalt oil and rubber skid marks are examples. Loose dirt can be removed by pressure washing, perhaps using soap, brushing, or high-pressure air; however, these techniques are usually insufficient to remove dirt that is packed into the marking surface. Care should be taken to select areas that are typical of the marking section, avoiding areas of paint tracking or contamination, for example. It may be useful to take photographs using a digital camera and a good macro lens to be able to see the contamination on or between the glass beads. SCOPE 1.1 This practice describes several field techniques to evaluate the retroreflective properties of pavement markings containing retroreflecting optics (for example, centerlines and edgelines) and applied to the road surface. The techniques described in this practice contain sampling criteria such as the length of test sections and the number of measurements needed. The practice is based on retroreflective measurements made with portable hand-operated instruments in compliance with Test Method E1710. 1.2 The data obtained from this practice can be used to determine the acceptance or rejection of a project based on specified levels of retroreflectivity established by the agency having jurisdiction. 1.3 This practice can be used for the evaluation of newly installed or existing pavement markings. When testing newly applied pavement markings, it is recommended that the evaluation be done no sooner than 48 h after application but before 30 days after application so that excess retroreflective optics, such as glass spheres, are no longer present. 1.4 The assessment techniques in this practice are based on best practices and designed to provide three levels of confidence in terms of quantifying the retroreflective performance of markings. Each technique represents a tradeoff between the number of measurements and the confidence of the retroreflective performance of the markings under study. 1.5 This practice can be used by agencies as is or may be customized to meet an agency’s specific needs. Where applicable, the practice describes areas where different assumptions could be made, which would impact the sampling needs and the confidence levels of the results. When deviations from this practice are made, they shall be documented in the test report. Note 1: When measuring newly installed pavement markings, there are several factors that contribute to erroneous values for measurements made within a short time after application, such as excess retroreflective optics, top coatings on tape, incomplete curing of the binder, and coatings on the retroreflective optics. Retroreflective measurements taken within 48 h after application may be useful to quickly gauge the application quality but are not intended to be used with this practice. Note 2: When measuring existing or in-service pavement markings, care should be ta...
SIGNIFICANCE AND USE 5.1 This practice provides procedures for the determination of the retroreflective performance of pavement markings. This practice does not set the minimum retroreflectance values for pavement markings; it describes sampling criteria for determining the retroreflective properties of pavement markings, which then can be used to determine compliance with a specification. It is the responsibility of the agency having jurisdiction to set the acceptable retroreflectivity values within their own specifications. 5.2 This practice does not purport to address all the concerns regarding contamination of the markings, but the following may be helpful. It is very important that the markings being evaluated are clean and dry. If the evaluation is being used relative to a measure of the performance of a contractor, it is imperative that the parties agree beforehand on the definition of clean and dry. There are many forms of contamination on a roadway that will lower the retroreflectivity readings of a marking, but not all of them can be removed. Asphalt oil and rubber skid marks are examples. Loose dirt can be removed by pressure washing, perhaps using soap, brushing, or high-pressure air; however, these techniques are usually insufficient to remove dirt that is packed into the marking surface. Care should be taken to select areas that are typical of the marking section, avoiding areas of paint tracking or contamination, for example. It may be useful to take photographs using a digital camera and a good macro lens to be able to see the contamination on or between the glass beads. SCOPE 1.1 This practice describes several field techniques to evaluate the retroreflective properties of pavement markings containing retroreflecting optics (for example, centerlines and edgelines) and applied to the road surface. The techniques described in this practice contain sampling criteria such as the length of test sections and the number of measurements needed. The practice is based on retroreflective measurements made with portable hand-operated instruments in compliance with Test Method E1710. 1.2 The data obtained from this practice can be used to determine the acceptance or rejection of a project based on specified levels of retroreflectivity established by the agency having jurisdiction. 1.3 This practice can be used for the evaluation of newly installed or existing pavement markings. When testing newly applied pavement markings, it is recommended that the evaluation be done no sooner than 48 h after application but before 30 days after application so that excess retroreflective optics, such as glass spheres, are no longer present. 1.4 The assessment techniques in this practice are based on best practices and designed to provide three levels of confidence in terms of quantifying the retroreflective performance of markings. Each technique represents a tradeoff between the number of measurements and the confidence of the retroreflective performance of the markings under study. 1.5 This practice can be used by agencies as is or may be customized to meet an agency’s specific needs. Where applicable, the practice describes areas where different assumptions could be made, which would impact the sampling needs and the confidence levels of the results. When deviations from this practice are made, they shall be documented in the test report. Note 1: When measuring newly installed pavement markings, there are several factors that contribute to erroneous values for measurements made within a short time after application, such as excess retroreflective optics, top coatings on tape, incomplete curing of the binder, and coatings on the retroreflective optics. Retroreflective measurements taken within 48 h after application may be useful to quickly gauge the application quality but are not intended to be used with this practice. Note 2: When measuring existing or in-service pavement markings, care should be ta...
ASTM D7585/D7585M-10(2022) is classified under the following ICS (International Classification for Standards) categories: 93.080.20 - Road construction materials. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM D7585/D7585M-10(2022) has the following relationships with other standards: It is inter standard links to ASTM E808-23, ASTM D4061-13(2018), ASTM E1710-18, ASTM E808-01(2016), ASTM E284-13b, ASTM D4061-13, ASTM E284-13a, ASTM E284-13, ASTM E284-12, ASTM E1710-11, ASTM E284-09a, ASTM E808-01(2009), ASTM E284-09, ASTM E284-08, ASTM E284-07. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM D7585/D7585M-10(2022) is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
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: D7585/D7585M −10 (Reapproved 2022)
Standard Practice for
Evaluating Retroreflective Pavement Markings Using
Portable Hand-Operated Instruments
This standard is issued under the fixed designation D7585/D7585M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
are several factors that contribute to erroneous values for measurements
1. Scope
made within a short time after application, such as excess retroreflective
1.1 This practice describes several field techniques to evalu-
optics, top coatings on tape, incomplete curing of the binder, and coatings
ate the retroreflective properties of pavement markings con- on the retroreflective optics. Retroreflective measurements taken within
48 h after application may be useful to quickly gauge the application
taining retroreflecting optics (for example, centerlines and
quality but are not intended to be used with this practice.
edgelines) and applied to the road surface. The techniques
NOTE 2—When measuring existing or in-service pavement markings,
described in this practice contain sampling criteria such as the
care should be taken so that representative sections of pavement markings
length of test sections and the number of measurements
are measured. There are particular conditions where excessive pavement
needed. The practice is based on retroreflective measurements marking wear can be associated with a specific cause such as vehicle
tracking along horizontal curves, access points to gravel pits, and high
made with portable hand-operated instruments in compliance
weave areas. Pavement markings can also collect dirt, grime, and debris.
with Test Method E1710.
1.6 This practice replaces Specification D6359 with a multi-
1.2 The data obtained from this practice can be used to
level strategy for evaluating the retroreflectance of pavement
determine the acceptance or rejection of a project based on
marking materials. This change was desired to provide agen-
specified levels of retroreflectivity established by the agency
cies with options for project acceptance and monitoring of
having jurisdiction.
pavement markings during service.
1.3 This practice can be used for the evaluation of newly
1.7 The values stated in either SI units or inch-pound units
installed or existing pavement markings. When testing newly
are to be regarded separately as standard. The values stated in
applied pavement markings, it is recommended that the evalu-
each system may not be exact equivalents; therefore, each
ation be done no sooner than 48 h after application but before
system shall be used independently of the other. Combining
30 days after application so that excess retroreflective optics,
values from the two systems may result in nonconformance
such as glass spheres, are no longer present.
with the standard.
1.4 The assessment techniques in this practice are based on
1.8 This standard does not purport to address all of the
best practices and designed to provide three levels of confi-
safety concerns, if any, associated with its use. It is the
dence in terms of quantifying the retroreflective performance
responsibility of the user of this standard to establish appro-
of markings. Each technique represents a tradeoff between the
priate safety, health, and environmental practices and deter-
number of measurements and the confidence of the retroreflec-
mine the applicability of regulatory limitations prior to use.
tive performance of the markings under study.
1.9 This international standard was developed in accor-
1.5 This practice can be used by agencies as is or may be
dance with internationally recognized principles on standard-
customized to meet an agency’s specific needs. Where
ization established in the Decision on Principles for the
applicable, the practice describes areas where different as-
Development of International Standards, Guides and Recom-
sumptions could be made, which would impact the sampling
mendations issued by the World Trade Organization Technical
needs and the confidence levels of the results.When deviations
Barriers to Trade (TBT) Committee.
from this practice are made, they shall be documented in the
2. Referenced Documents
test report.
2.1 ASTM Standards:
NOTE 1—When measuring newly installed pavement markings, there
D4061 Test Method for Retroreflectance of Horizontal Coat-
ings
This practice is under the jurisdiction of ASTM Committee D04 on Road and
Paving Materials and is the direct responsibility of Subcommittee D04.38 on
Highway Traffic Control Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2022. Published May 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2010. Last previous edition approved in 2015 as D7585/D7585M – 10 Standards volume information, refer to the standard’s Document Summary page on
(2015). DOI: 10.1520/D7585_D7585M-10R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7585/D7585M − 10 (2022)
D6359 Specification for Minimum Retroreflectance of 4.2.1 A nighttime visual inspection protocol to inspect the
Newly Applied Pavement Marking Using Portable Hand- appearance of the markings and identify sections that appear to
Operated Instruments (Withdrawn 2006) have inadequate retroreflectivity levels.
E284 Terminology of Appearance 4.2.2 A standard evaluation protocol, which provides a
E808 Practice for Describing Retroreflection
reasonable measure of assurance that the retroreflectivity data
E1710 Test Method for Measurement of Retroreflective collected with handheld devices is representative of the mark-
Pavement Marking Materials with CEN-Prescribed Ge-
ings being evaluated. The protocol was designed to require a
ometry Using a Portable Retroreflectometer minimum number of measurements while maintaining confi-
dence with the results.
3. Terminology
4.2.3 Amorerigorousevaluationprotocol,whichprovidesa
3.1 The terms and definitions in Terminology E284 and
higherlevelofassurancethattheretroreflectivitydatacollected
Practice E808 are applicable to this specification.
with handheld devices is representative of the marking being
evaluated. This protocol requires an intensive measurement
3.2 Definitions of Terms Specific to This Standard:
protocol and should be used as the referee method to resolve
3.2.1 acceptable quality level, AQL, n—the maximum per-
disputes regarding the status of a marking.
cent defective that, for purposes of sampling inspection, can be
considered satisfactory as a process average (that is, the
4.3 The three assessment techniques described in 4.2 were
percent defective that can be tolerated without impairing
designed so that they could be used independently of one
performance).
another. In other words, an agency can specify the use of a
3.2.1.1 Discussion—Thisisthemaximumallowablepropor-
specific assessment technique, a combination, or all three.
tion of pavement marking readings with values below specifi-
Furthermore, they are not meant to be used sequentially for all
cation.
evaluations, but that is certainly an option.
3.2.2 evaluation section—the specific area of the pavement
5. Significance and Use
marking along which measurements will be made.
3.2.3 limit quality, LQ, n—limit of the AQL that is
5.1 This practice provides procedures for the determination
acceptable, providing a specified limited quality for protection.
of the retroreflective performance of pavement markings. This
3.2.3.1 Discussion—This is the proportion of pavement
practice does not set the minimum retroreflectance values for
marking readings with values below the acceptable level,
pavement markings; it describes sampling criteria for deter-
which in the worst case, would be allowed.
mining the retroreflective properties of pavement markings,
which then can be used to determine compliance with a
3.2.4 producer’s risk—the risk the producer of the marking
specification. It is the responsibility of the agency having
takes that the marking will fail the requirement specified when
jurisdiction to set the acceptable retroreflectivity values within
the marking is actually acceptable.
their own specifications.
3.2.4.1 Discussion—Ifthepopulationoftheentirepavement
marking fulfills the specification, there is still the probability
5.2 This practice does not purport to address all the con-
that the sampling of the marking will fall below the required
cerns regarding contamination of the markings, but the follow-
level as specified. This is designated the α risk (alpha risk).
ingmaybehelpful.Itisveryimportantthatthemarkingsbeing
evaluated are clean and dry. If the evaluation is being used
3.2.5 user’s risk—the risk the owner of the marking takes
relative to a measure of the performance of a contractor, it is
that the marking will meet the requirement specified when the
imperativethatthepartiesagreebeforehandonthedefinitionof
marking retroreflectivity is actually substandard.
clean and dry. There are many forms of contamination on a
3.2.5.1 Discussion—Ifthepopulationoftheentirepavement
roadway that will lower the retroreflectivity readings of a
marking fails the specification, there is still the probability that
the sampling of the marking will equal or exceed the required marking, but not all of them can be removed. Asphalt oil and
rubber skid marks are examples. Loose dirt can be removed by
level as specified. This is designated the β risk (beta risk).
pressure washing, perhaps using soap, brushing, or high-
4. Summary of Practice
pressure air; however, these techniques are usually insufficient
to remove dirt that is packed into the marking surface. Care
4.1 This practice does not set the minimum retroreflectance
should be taken to select areas that are typical of the marking
values for newly installed pavement markings or minimum
section, avoiding areas of paint tracking or contamination, for
maintenance levels of pavement markings. It is the responsi-
example. It may be useful to take photographs using a digital
bility of the agency having jurisdiction to set the acceptable
retroreflectivity values within their specifications. camera and a good macro lens to be able to see the contami-
nation on or between the glass beads.
4.2 This practice describes assessment techniques (includ-
ing sampling criteria) to evaluate the retroreflective perfor-
6. Procedure
mance of pavement markings, which can then be used to
determine compliance to a referenced specification. More
6.1 Standardization of Portable Hand-Operated Retrore-
specifically, this practice includes: flective Measurement Instruments:
6.1.1 Before taking measurements, the retroreflectometer(s)
shall be standardized with an instrument standard as defined in
The last approved version of this historical standard is referenced on
www.astm.org. Test Method D4061.
D7585/D7585M − 10 (2022)
6.1.2 When more than one instrument is used, the instru- be defined by the agency having jurisdiction, particularly if the
ments should be compared to a known standard in order to Nighttime Visual Inspection Protocol described in 6.2 is not
determine the characteristics of the specific instrument. These used.
characteristics should be noted and taken into account when 6.3.4 The evaluation sections should be at least 400 ft
recording values.
[125 m] and clearly identified. There should be at least three
evaluation sections per pavement marking of interest (unless
6.2 Nighttime Visual Inspection Protocol:
the pavement marking of interest is less than 2 miles [3 km], in
6.2.1 This technique may be used to assess newly installed
which case a minimum of one evaluation section is needed).
markings, and to assess the performance of in-service mark-
For pavement marking lines longer than 10 miles [16 km], the
ings. This technique may be used to assess all types of
agencyhavingjurisdictionmayelecttospecifymorethanthree
pavement markings.
evaluation sections (such as three evaluation sections per
6.2.2 Schedule a night to conduct the visual inspection of
10 miles [16 km]). Measurements should be taken at regular
the project so that the pavement markings are dry and the
intervals throughout the evaluation section. For lane lines and
ambient weather conditions are free of rain, fog, or other types
broken centerlines, two measurements should be taken on each
of precipitation.
skip line.
6.2.3 A representative automobile or light passenger truck
6.3.5 Once safe conditions are provided, portable hand-
shall be used for the inspection. The headlamps shall be in
operated retroreflective measurements can be taken for each
good working condition and aimed correctly.
evaluation section. The intent is to take enough measurements
6.2.4 The inspection shall be conducted in full nighttime
to be confident that the mean of the measurements is close to
conditions (after civil twilight) with the vehicle headlamps on
the true mean retroreflectivity of the measurement section
low beam.
while minimizing the number of measurements needed. The
6.2.5 Inspect all the markings visually through the wind-
recommended number of measurements is 16 per section, as
shield while driving at the posted speed.
described in Annex A1.
6.2.6 Look for areas that appear to lack the luminance
6.3.6 Once the measurements are recorded, calculate the
expected based on the specified retroreflectivity or lack the
average to determine a single retroreflectivity value represen-
expected uniformity. Look for inconsistent areas where the
tative for the evaluation section. This average value represents
luminance is below what could be expected for the pavement
the retroreflectivity of the pavement
...




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