ASTM D8379/D8379M-21

Standard Practice for Evaluating Nighttime Retroreflective Sheeting Effectiveness Using Positive-Contrast Textual Sign Scenario Performance Analysis

SIGNIFICANCE AND USE
5.1 Retroreflective sheeting is commonly used to improve the nighttime visibility and legibility of traffic signs under vehicle headlight illumination. This standard provides a procedure for evaluating the nighttime retroreflective performance of sign sheeting used in roadway signing in terms of an overall average performance index for predefined road scenarios.  
5.2 A procedure to characterize the relationship between sign luminance supply and driver luminance demand at night without conducting field work helps traffic engineers and transportation agencies responsible for specifying highway construction materials and maintaining roadway safety in making informed decisions about the performance of retroreflective sheeting on the signs. The procedure requires the comprehensive measurement of the retroreflective properties of a sheeting according to Practice E809 over a wide range of angles.  
5.3 A variety of retroreflective sheeting is available for use on traffic signs. Coefficients of retroreflection are typically measured for a standard set of angle combinations and are used, in part, to certify conformance to a specification or standard. However, while coefficients of retroreflection on some standard angle sets can provide a general idea about a sheeting’s retroreflectivity and help certify conformance to a standard, a more comprehensive analysis is needed to determine how well a sheeting is expected to serve drivers in general, or in specific use-cases. Drivers of different vehicles viewing a multitude of signs in the real world experience a much more complex set of angular combinations than those captured in the standard angle sets. Furthermore, drivers observe luminance, which is affected by not only the coefficient of retroreflection, but also by headlight illumination, distance from the vehicle to the sign, and light attenuation, among other factors.  
5.4 This practice utilizes a set of driver sign viewing scenarios. When combined with the coefficients...
SCOPE
1.1 This practice provides a framework to evaluate retroreflective sheeting performance in nighttime driving conditions without a need for field evaluations through a set of sign viewing scenarios representing common use-cases. The evaluation of performance of a specific sheeting is achieved by comparing the luminance provided by a sheeting to the luminance needed by drivers in each scenario. This comparison is expressed in terms of a “Performance Index,” which is a measure for how well the luminance provided to the driver meets their needs, in each of the scenarios. Comparison of the performance index values for different sheeting allows the user to predict differences in nighttime retroreflective performance when those sheeting are used on installed signs.  
1.2 The driver-needs data is based on textual signs (not on symbolic signs) with positive contrast (sign text being brighter than its background), and the headlamp illumination is assumed to be low-beams; therefore, performance index is applicable only to textual signs viewed under low-beam headlamp illumination.  
1.3 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The value stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.  
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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 Recommenda...

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 01.080.10 - Public information symbols. Signs. Plates. Labels
• Technical Committee: D04 - Road and Paving Materials
• Drafting Committee: D04.38 - Highway Traffic Control Materials

Relations

• Refers: ASTM E808-23 - Standard Practice for Describing Retroreflection
• Effective Date: 01-Dec-2023
• Refers: ASTM D8-19 - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Aug-2019
• Refers: ASTM D8-18c - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 15-Dec-2018
• Refers: ASTM D8-18b - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 15-Aug-2018
• Refers: ASTM D8-18a - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Jul-2018
• Refers: ASTM D8-18 - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Feb-2018
• Refers: ASTM D8-17c - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 15-Jul-2017
• Refers: ASTM D8-17b - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 15-Jun-2017
• Refers: ASTM D8-17a - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-May-2017
• Refers: ASTM D8-17 - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Mar-2017
• Refers: ASTM D8-16b - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Dec-2016
• Refers: ASTM D8-16a - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 15-Sep-2016
• Refers: ASTM D8-16 - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Sep-2016
• Refers: ASTM E808-01(2016) - Standard Practice for Describing Retroreflection
• Effective Date: 01-Jan-2016
• Refers: ASTM D8-15 - Standard Terminology Relating to Materials for Roads and Pavements
• Effective Date: 01-Sep-2015

Overview

ASTM D8379/D8379M-21 is an international standard developed by ASTM International that outlines a practice for evaluating the effectiveness of nighttime retroreflective sheeting on roadway signage. The primary objective of this standard is to provide a framework for assessing the performance of retroreflective materials used on positive-contrast textual traffic signs (where the sign text is brighter than the background) during nighttime driving conditions, particularly under low-beam headlight illumination. The evaluation focuses on how well these materials meet drivers' luminance needs using scenario-based performance analysis, removing the need for costly and time-consuming field tests.

Key Topics

• Performance Index Approach: The standard introduces the concept of a "Performance Index," which compares the luminance supplied by a retroreflective sheeting to the luminance required by drivers across a variety of typical sign viewing scenarios.
• Scenario-Based Analysis: It utilizes multiple predefined sign viewing scenarios that take into account factors such as sign placement, vehicle type, letter size on the sign, scene complexity, distance to the sign, and variability in headlight intensity.
• Laboratory Evaluation: The method allows traffic engineers and transportation agencies to objectively measure and predict the nighttime retroreflective effectiveness of sign sheeting without field installation, leveraging comprehensive lab-based photometric measurements.

Applications

The ASTM D8379/D8379M-21 standard serves several practical applications relevant to roadway safety and material specification:

• Traffic Safety Improvement: By providing a quantifiable and repeatable way to predict how well various retroreflective sheetings perform for different vehicle types and driving conditions, agencies can better select materials that enhance nighttime visibility and sign legibility.
• Efficient Material Selection: Engineers responsible for specifying highway construction materials can use this practice to make informed decisions, ensuring chosen retroreflective sheetings will provide required performance across common use-cases.
• Compliance and Maintenance: The standard supports conformance testing and long-term maintenance strategies by allowing comparisons between different retroreflective products, ensuring ongoing compliance with safety standards and performance requirements.
• Resource Optimization: By eliminating the necessity for on-road testing in evaluating retroreflectivity under varied real-world conditions, the standard saves time and resources for municipalities and contractors.

Related Standards

• ASTM E809: Practice for Measuring Photometric Characteristics of Retroreflectors - serves as a referenced method for measuring the necessary retroreflective properties of sheeting materials.
• ASTM E808: Practice for Describing Retroreflection - establishes terminology and basic concepts used in retroreflective measurements.
• ASTM D8: Terminology Relating to Materials for Roads and Pavements - relevant for technical definitions.
• ASTM E284: Terminology of Appearance - supports consistency in describing visual characteristics.
• BS 8408:2005: Road Traffic Signs. Testing and Performance of Microprismatic Retroreflective Sheeting Materials (Withdrawn) - offers historical context and alternate testing frameworks.

Conclusion

ASTM D8379/D8379M-21 provides a systematic, scenario-based practice for evaluating the nighttime retroreflective effectiveness of positive-contrast textual traffic signs. Through its Performance Index methodology and use-case-based lab analysis, the standard empowers transportation agencies, engineers, and materials specifiers to ensure roadway signs meet visibility and legibility needs, directly supporting roadway safety and public compliance. By leveraging related ASTM standards, users benefit from a harmonized approach to retroreflective measurement and performance assessment, strengthening overall traffic control infrastructure and minimizing maintenance costs.

Keywords: ASTM D8379, retroreflective sheeting, nighttime sign visibility, performance index, roadway safety, traffic sign evaluation, laboratory testing, luminance demand, headlight illumination, transportation engineering.

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:D8379/D8379M −21
Standard Practice for
Evaluating Nighttime Retroreflective Sheeting Effectiveness
Using Positive-Contrast Textual Sign Scenario Performance
Analysis
This standard is issued under the fixed designation D8379/D8379M; 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.
1. Scope Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 This practice provides a framework to evaluate retrore-
Barriers to Trade (TBT) Committee.
flective sheeting performance in nighttime driving conditions
without a need for field evaluations through a set of sign
2. Referenced Documents
viewing scenarios representing common use-cases. The evalu-
2.1 ASTM Standards:
ation of performance of a specific sheeting is achieved by
B209/B209MSpecification for Aluminum and Aluminum-
comparing the luminance provided by a sheeting to the
Alloy Sheet and Plate
luminanceneededbydriversineachscenario.Thiscomparison
B449Specification for Chromates on Aluminum
is expressed in terms of a “Performance Index,” which is a
D8Terminology Relating to Materials for Roads and Pave-
measure for how well the luminance provided to the driver
ments
meets their needs, in each of the scenarios. Comparison of the
E284Terminology of Appearance
performanceindexvaluesfordifferentsheetingallowstheuser
E808Practice for Describing Retroreflection
to predict differences in nighttime retroreflective performance
E809Practice for Measuring Photometric Characteristics of
when those sheeting are used on installed signs.
Retroreflectors
1.2 The driver-needs data is based on textual signs (not on
2.2 BSI Standard:
symbolic signs) with positive contrast (sign text being brighter
BS 8408:2005Road Traffic Signs. Testing and Performance
than its background), and the headlamp illumination is as-
of Microprismatic Retroreflective Sheeting Materials.
sumed to be low-beams; therefore, performance index is
Specification (Withdrawn)
applicable only to textual signs viewed under low-beam
3. Terminology
headlamp illumination.
3.1 Definitions—For definitions of technical terms used in
1.3 Units—The values stated in either SI units or inch-
this practice, see Terminologies D8 and E284.
pound units are to be regarded separately as standard. The
value stated in each system may not be exact equivalents;
3.2 Definitions of Terms Specific to This Standard:
therefore,eachsystemshallbeusedindependentlyoftheother.
3.2.1 legibility index, n—a surrogate metric for the size of
Combining values from the two systems may result in noncon-
the image on the retina, expressed in terms of the longitudinal
formance with the standard.
(roadway) distance to the sign divided by the height of the
uppercase alphanumeric on the text.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.2 legibility range, n—the range of distances to a sign,
responsibility of the user of this standard to establish appro-
expressed longitudinally along the roadway centerline, that are
priate safety, health, and environmental practices and deter- between a legibility index of 40 ft/in. [4.8 m/cm] and 20 ft/in.
mine the applicability of regulatory limitations prior to use.
[2.4 m/cm].
1.5 This international standard was developed in accor-
3.2.3 performance index, n—a measure that approximates a
dance with internationally recognized principles on standard-
sign sheeting’s performance, in terms of luminance observed
ization established in the Decision on Principles for the
by the driver, in a given scenario.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This practice is under the jurisdiction of ASTM Committee D04 on Road and contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Paving Materials and is the direct responsibility of Subcommittee D04.38 on Standards volume information, refer to the standard’s Document Summary page on
Highway Traffic Control Materials. the ASTM website.
Current edition approved Nov. 1, 2021. Published December 2021. DOI: Available from British Standards Institution (BSI), 389 Chiswick High Rd.,
10.1520/D8379_D8379M-21. London W4 4AL, U.K., http://www.bsigroup.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8379/D8379M−21
3.2.4 R multiplier, n—afactorderivedfromtheilluminance 4.2.7 Calculate the overall performance index for each
A
at the sign per headlight, measured facing the headlight in a scenario by averaging the performance indexes calculated for
scenario,whilealsoincorporatingwindshieldtransmissionand each distance and each headlight percentile.
the cosine of viewing angle. 4.2.8 An example walkthrough for the calculation of per-
formance index for one of the scenarios is provided in Annex
3.2.4.1 Discussion—R multiplier is defined at each dis-
A
A2.
tance for a single headlight, and when multiplied by the
coefficientofretroreflectionforthecorrespondingscenarioand
5. Significance and Use
distance,theresultistheluminanceobservedbythedriver.The
formula for obtaining the R multipliers is given in Appendix
A 5.1 Retroreflective sheeting is commonly used to improve
X1.
the nighttime visibility and legibility of traffic signs under
vehicle headlight illumination. This standard provides a pro-
3.2.5 scenario, n—a particular use-case for retroreflective
cedureforevaluatingthenighttimeretroreflectiveperformance
sign sheeting, determined by sign mounting location, vehicle
ofsignsheetingusedinroadwaysigningintermsofanoverall
type,thesizeofthetextonthesign,andthesurroundingscene
average performance index for predefined road scenarios.
complexity, as viewed by the driver within the legibility range.
5.2 A procedure to characterize the relationship between
4. Summary of Practice
sign luminance supply and driver luminance demand at night
without conducting field work helps traffic engineers and
4.1 This practice outlines a procedure to calculate the
transportation agencies responsible for specifying highway
performance index of a retroreflective sheeting by comparing
construction materials and maintaining roadway safety in
the luminance provided by the sheeting, to the luminance
making informed decisions about the performance of retrore-
required by the driver in a set of nighttime traffic sign viewing
flective sheeting on the signs. The procedure requires the
scenarios.
comprehensivemeasurementoftheretroreflectivepropertiesof
4.2 The procedure requires the following steps:
a sheeting according to Practice E809 over a wide range of
4.2.1 Obtain retroreflective sheeting,
angles.
4.2.2 Prepare samples,
5.3 A variety of retroreflective sheeting is available for use
4.2.3 Select the scenarios of interest, for example, vehicle
on traffic signs. Coefficients of retroreflection are typically
types, sign locations, and letter heights as defined in Table
measured for a standard set of angle combinations and are
A1.1.
used, in part, to certify conformance to a specification or
4.2.3.1 Determinethecorrespondingapplicabletablesunder
standard. However, while coefficients of retroreflection on
the“MeasurementAnglesandR MultiplierTable”columnfor
A
some standard angle sets can provide a general idea about a
the selected scenario(s) in Table A1.1 (Table A1.3 through
sheeting’s retroreflectivity and help certify conformance to a
Table A1.11). Also determine the corresponding performance
standard, a more comprehensive analysis is needed to deter-
index table(s) for the same scenarios under the “Performance
mine how well a sheeting is expected to serve drivers in
Index Table” column for later use in 4.2.6.
general, or in specific use-cases. Drivers of different vehicles
viewing a multitude of signs in the real world experience a
NOTE 1—Table A1.3 through Table A1.11 provide the pre-determined
much more complex set of angular combinations than those
measurement angles for the sheeting representing the angular combina-
tions under which the sheeting is observed by the driver in the corre-
captured in the standard angle sets. Furthermore, drivers
spondingscenarios.Iftheuserisnotconsideringallscenariosatthistime,
observeluminance,whichisaffectedbynotonlythecoefficient
it is still recommended that all pre-determined angular sets in TableA1.3
of retroreflection, but also by headlight illumination, distance
through TableA1.11 are considered for measurement for future purposes.
fromthevehicletothesign,andlightattenuation,amongother
4.2.4 Measure sheeting R values for the set of pre-defined
A
factors.
measurementanglesgiveninthecorresponding“Measurement
5.4 This practice utilizes a set of driver sign viewing
Angles and R Multiplier Table(s)” Table A1.3 through Table
A
scenarios. When combined with the coefficients of retroreflec-
A1.11.
tion at the corresponding geometry, the luminance as observed
4.2.5 Calculate the luminance observed by the driver for
by the driver is calculated. The luminance requirements of the
selected scenario(s) by multiplying the R values (from 4.2.4)
A
driver for varying percentiles are also tabulated for the user.
withthecorrespondingR Multipliers,whicharealsogivenin
A
Comparing the luminance supply from the sign with the
Table A1.3 through Table A1.11 for right and left headlights
luminance demand of drivers provides an assessment of the
separately, and add the luminance from the right and left
expected “performance index” in each scenario.
headlights to determine total observed luminance. Do this
5.5 Thedataontheluminanceneedsofthedriverrepresents
calculation for each distance and for all three distinct
th th th
thevisualperformanceofasubsetoflegaldriversintheUnited
headlights, representing the 25 ,50 , and the 75 percentile
States of 55 years of age or older and may not represent the
low-beams.
visual performance of the entire driver demographics.
4.2.6 Calculate the performance index for each of the
selectedscenarios,ateachdistanceandheadlightpercentile,by
6. Scenarios
comparing the observed luminance (from 4.2.5) to the lumi-
nance required by the driver given tables in Annex A1, given 6.1 A scenario refers to any unique combination of the
in Table A1.12 through Table A1.15. variables listed in 6.2.1 – 6.2.4, at the levels outlined in Table
D8379/D8379M−21
th
1 in 6.3. The three distinct headlight percentile levels (25 6.4.1.2 Sign Placement—Three sign locations: (1) left
th th
percentile, 50 percentile, and 75 percentile) do not each shoulder mounted, (2) right shoulder mounted, and (3) over-
yield a different scenario but collectively make up a single
head mounted. Dimensions for sign placement are given in
scenario. This ensures the effect of headlight variability to be
6.5.5.
incorporated into the performance index calculations. For
6.4.1.3 Vehicle Type—Three vehicle types: (1) heavy
clarity, the variables are given in three groups: the ones that
vehicle,(2)sedan,and(3)SUV.Thepositionsofthedriverand
affect the luminance provided by the sheeting, the ones that
the headlights for each vehicle type are given in 6.5.5.
affect the luminance required by the driver, and the ones that
affect both. The full list of scenarios referenced with scenarios
NOTE 2—Vehicle type primarily affects the location of the driver and
numbers are given in Annex A1. thelocationoftheheadlights,changingtheviewinggeometryatwhichthe
coefficient of retroreflection has to be measured.
6.2 Variables—Five variables known to affect the sign
th
luminance observed or needed by the driver are identified to 6.4.1.4 Headlamps—Three headlamps: (1) UMTRI 25
th th
define the sign use-case scenarios. These variables are as
percentile, (2) UMTRI 50 percentile, and (3) UMTRI 75
follows:
percentile low-beams, all 2011 data for vehicles sold in the
6.2.1 Sign placement,
U.S. market. The headlamp luminous intensity matrices as a
6.2.2 Vehicle type,
function of vertical and horizontal beam angles are given in
6.2.3 Letter size on sign,
Table A1.2.
6.2.4 Visual complexity of the sign’s surroundings, and
6.4.2 Variables That Affect the Luminance Needed By the
6.2.5 Headlamps.
Driver:
6.3 Variable Levels—The scenarios consist of all combina-
6.4.2.1 Visual Complexity—Two levels: (1) Low/Medium,
tionsoftheabovevariables,atlevelsindicatedinTable1.Each
and (2) High. Visual complexity does not affect the luminance
scenario shall also incorporate the fixed parameters given in
provided by the sheeting, but it affects the luminance needed
6.5. There is a total of 36 scenarios (three sign locations, three
by the driver. In general, signs located in areas with higher
vehicle types, two letter sizes, and two visual complexity
nighttimevisualcomplexityrequirehigherlevelsofluminance
levels). Each scenario contains all three headlight percentiles
to provide the same level of service to drivers.
and is given a scenario number as given in Table A1.1. The
6.4.2.2 Letter Size—Two letters heights: (1)12in.
Tables in A1.1.3 and A1.1.4 provide the relevant angles,
[0.3048m], and (2) 16 in. [0.4064 m] letter heights. At any
multipliers for luminance calculation, and the demand
given distance, letter size has a direct effect on the luminance
luminances, and are referenced to the applicable scenario
numbers for clarity. needed for legibility. Although letter size does not affect the
luminance observed by the driver, it affects the legibility range
6.4 Variable Groups—The scenario variables are divided in
in terms of absolute distance to the sign. A discussion of the
three groups: (1) variables that affect the luminance provided
general practice in letter size as a function of roadway
bythesheeting,(2)variablesthataffecttheluminancerequired
classification is given in Appendix X2.
by the driver, and (3) variables that affect both the luminance
provided by the sheeting and the luminance required by the
6.4.3 Variables That Affect Both the Luminance Provided By
driver.
the Sheeting and the Luminance Needed By the Driver:
6.4.1 Variables That Affect Sign Luminance As Observed By
6.4.3.1 Distance to Sign—The distance to the sign (as
the Driver:
measured between two parallel vertical planes, one containing
6.4.1.1 Retroreflective sheeting.
the vehicle headlights and the other containing the sign center)
in all scenarios shall include the legibility range for the
correspondingletterheight.Inallscenarios,distancesaregiven
in 10-ft intervals and calculations shall be performed at each
TABLE 1 Selected Variables and Corresponding Levels for
distance. The user shall use the appropriate distance range for
Standard Sign Viewing Scenarios
the selected letter height. Because a large portion of these two
Variable Level
distance ranges overlap, they are combined in Table A1.3
Sign Placement Right Shoulder
Left Shoulder through Table A1.11 for both letter heights.
Overhead
(1)For 16 in. [40.64 cm] letter height scenarios, only the
distance range of 640 ft to 320 ft [192.07 m to 97.54 m] shall
Vehicle Type Sedan
SUV/Minivan/LT
be used.
HV
(2)For 12 in. [30.48 cm] letter height, only the 480 ft to
th th th
Headlamps UMTRI 25 ,50 ,75 percentile U.S. 2011 240 ft [146.3 m to 73.15 m].
low-beam headlights (Schoettle et al. (1))
6.5 Dimensions, Fixed and Dependent Parameters—Values
Visual Complexity Low/Medium
for some additional parameters known to affect sign
High (without sign lighting)
performance, as well as the dimensions for the three sign
Letter Size Small (12 in. [0.3048 m])
placements and three vehicle types, shall be as follows.
Large (16 in. [0.4064 m])
6.5.1 Roadway Geometry—Roadway is straight and level.
D8379/D8379M−21
TABLE 2 Headlight and Driver Eye Positions for Three Vehicle
6.5.2 Windshield Transmission Factor—Awindshield trans-
Types
mission factor of 72% has been used in the calculation of R
A
Vehicle Dimensions and Relative Driver Eye Positions ft [m]
multipliers (UMTRI (2)).
Vehicle Type h h s s s
1 2 1 2 3
6.5.2.1 Anautomobilewindshieldactssimilarlytoaneutral
A
Passenger Car 2.13 [0.65] 3.93 [1.20] 3.27 [1.00] 0.66 [0.20] 6.55 [2.00]
densityfilterinthevisiblespectrum,reducingtheluminanceof
A
SUV/Minivan/LT 2.72 [0.83] 4.66 [1.42] 4.26 [1.30] 0.75 [0.23] 6.82 [2.08]
B
the objects seen by the driver behind it. The R multipliers
Large Truck 3.57 [1.09] 7.68 [2.34] 6.17 [1.88] 1.35 [0.41] 7.22 [2.20]
A
provided in this standard include the effect of windshield A
BS 8408.
B
Sivak et al. (4).
transmission, and when multiplied by the corresponding coef-
ficient of retroreflection, yield the luminance as observed by
the driver behind a windshield. No further correction in
point on the road surface on the vertical plane consisting the
luminance is required by the user.
headlights, at an equal distance to the two headlights.
6.5.3 Sign Tilt and Twist—Right and left shoulder-mounted
6.6 Demand Luminance (Drivers’ Need for Luminance)—
signs shall have a twist of 4° outward (sign axis, which is
Demand luminance is the luminance of the brighter portion of
perpendicular to the sign surface, pointing away from the
the sign needed to successfully read the sign by a given
roadway), and the overhead sign shall have a tilt of 4° upward
performance index as a function of legibility index and scene
(sign axis pointing upward and away from the roadway).
complexity.Adetailed expansion of the demand luminance for
6.5.4 The angles given in Table A1.3 through Table A1.11
each scenario, with the legibility indices converted to sign
incorporate sign tilt and twist, and as such, the coefficients of
viewing distances, is provided in Table A1.12 through Table
retroreflection shall be measured at the angles given in these
A1.15. Demand luminance generally follows a linear relation-
tables with no additional correction or adjustment by the user.
shipasafunctionoflegibilityindexwithinthelegibilityrange.
6.5.5 Sign Location—The standard sign locations are such
Therefore,linearinterpolationisusedtodeterminethedemand
that the center point of the sign coincides with the three
luminance for legibility indices between 20 ft/in. [2.4 m/cm]
locations shown as “LS,” “OV,” and “RS” in Fig. 1, for left
and 40 ft/in. [4.8 m/cm] in calculating the required luminance
shoulder, overhead, and right shoulder sign locations, respec-
values provided in Table A1.12 through Table A1.15.
tively. The distances from the sign center with respect to the
vehicle’s projected view on the plane formed by the sign
7. Procedure
centers are shown in Fig. 1.
7.1 Sampling—Aminimum of nine specimens shall be used
6.5.6 Vehicle Dimensions—Vehicle dimensions and driver
to determine coefficients of retroreflection for a sheeting.
eye locations are used in calculating the R multipliers for the
A
7.1.1 Thespecimensshallbecutfromthreedifferentrollsor
analysisaregiveninTable2.Thedefinitionsofthedimensions
sheets of retroreflective sheeting in new (unexposed) condition
inTable2aregiveninFig.2.Thevehiclereferencepointisthe
at least 1 yd [0.914 m] long,
7.1.2 Each roll should be taken from a different, commer-
ciallyavailablelot.Afullwidthby1yd[0.914m]longsample
is selected at random to represent the entire sheet, roll, or lot.
The boldface numbers in parentheses refer to a list of references at the end of
this standard.
FIG. 1Standard Sign Locations Designating the Center of the Sign (Carlson (3))
D8379/D8379M−21
FIG. 2Vehicle Dimensions (definitions of dimensions in Table 2)
7.1.3 Three specimens are taken from the selected sample. 7.3 Report the coefficients of retroreflection as the average
Thethreespecimensshallbespacedevenlyacross(left,center, of all nine specimen at each of the α, β , β , ε angles.
1 2
right) and spaced evenly down the specimen as shown in the
Determine the luminance observed by the driver:
examples in Fig. 3.
7.3.1 The luminance as observed by the driver in each
7.1.4 Panel Preparations—Unless otherwise specified, ap-
scenario shall be obtained by multiplying the coefficients of
ply the specimens of retroreflective material to smooth alumi-
retroreflection for the angle sets given in Table A1.3 through
num cut fromAlloy 6061-T6 or 5052-H38, in accordance with
TableA1.11,withthecorrespondingR multipliersinthesame
A
Specification B209/B209M. The sheets shall be 0.020 in. th th th
tables for each of the 25 ,50 , and the 75 percentile
[0.508 mm], 0.040 in. [1.016 mm], or 0.063 in. [1.600 mm] in
headlights.At a given distance, add the luminance provided by
thickness, and a minimum of 8 by 8 in. [200 by 200 mm].
the right headlight to the luminance provided by the left
Prepare the aluminum in accordance with Specification B449,
headlight, and note the total luminance at that distance.
Class 2, or degrease and lightly acid etch before the specimens
7.3.2 For 16 in. [40.64 cm] letter height scenarios, only the
are applied. Apply the specimens to the panels in accordance
distance range of 640 ft to 320 ft [192.07 m to 97.54 m] shall
with the manufacturer’s recommendations.
be used. For the 12 in. [30.48 cm] letter height, only the 480 ft
7.2 Measure Sheeting Coeffıcients of Retroreflection:
to 240 ft [146.3 m to 73.15 m] range shall be used.
7.2.1 Measure the coefficients of retroreflection R
A
–1 –2
(cd.lx .m ) as per Practice E809 for each of the nine
NOTE 3—At the end of this step, for each scenario, the user will have
specimensateachoftheα,β ,β ,ɛanglescorrespondingtothe three sets of luminances (one for each percentile headlights) for the
1 2
applicable distance range.
chosen scenario.
7.2.2 The coefficients of retroreflection shall be determined
7.4 Calculate Performance Index:
for the CIE goniometric angle sets (α, β , β , ε) given in Table
1 2
7.4.1 Comparethetotalluminanceobservedbythedriverto
A1.3 through Table A1.11.
the luminance required for different percentile drivers at each
7.2.2.1 The datum axis on the goniometer, as defined in
distance to determine the performance index at that distance.
Practice E808, represents the vertical axis on the sign, and as
Determine the applicable performance index table for the
such, the orientation of the sheeting on the goniometer (the
selected scenario (Table A1.12 through Table A1.15). To find
angle between the datum mark on the sheeting and the datum
the correct performance index table, see Table A1.1. At each
axis on the goniometer) represents the orientation of the
distance index, determine the two cells, which the total
sheeting on the sign. Therefore, if the sheeting’s performance
observed luminance from 7.3 falls in between.
at 0° orientation on the sign is of interest (datum mark on the
7.4.2 Determine the benchmark performance index given in
sheeting parallel to the vertical sign axis), the sheeting sample
the column headers for these two cells (in the top row).
shall be mounted such that datum mark on the sheeting is
aligned with the datum axis of the goniometer. For other Calculate the performance index, which will be between these
two benchmark performance indexes, by linear interpolation.
orientations, such as 45° or 90°, sheeting shall be mounted
accordingly. An example calculation is provided in Annex A1.
FIG. 3Examples of Proper Spacing for Samples
D8379/D8379M−21
7.4.3 If the total luminance from 7.3 exceeds the highest distances × 3 headlight percentiles). To calculate overall
valueontheright-mostcolumn,theperformanceindexshallbe performanceindex,computetheaverageofthese99individual
noted as “98.”
performanceindexes(or75inthecaseof12in.letterheights),
7.4.4 The lowest limit for PI is 10. If the total luminance which will be the single and final performance index for the
from 7.3 falls below the lowest value on the left-most column,
scenario.
the PI shall be below 10 without a definite value.
7.4.5 Repeat the above steps 7.4.1 and 7.4.2 for each
8. Report
headlight percentile.
8.1 Report the following:
7.4.6 The interpolation yields an individual performance
8.1.1 The evaluated retroreflective sheeting,
index at each of the distances for each of the three headlight
percentiles (99 total for 16 in. letter heights: 33 distances × 3 8.1.2 Scenario number(s) evaluated, and
8.1.3 The performance index for the scenario(s).
headlight percentiles, and 75 total for 12 in. letters: 25
ANNEXES
(Mandatory Information)
A1. PARAMETERS
A1.1 Data: A1.1.3 CIE Goniometric System Angles α, β , β , ε, and R
1 2 A
Multipliers for Each Sign Scenario—See Tables A1.3-A1.11.
A1.1.1 Scenario Numbers—See Table A1.1.
A1.1.4 Performance Index Luminance Requirement
A1.1.2 Headlamp Luminous Intensity Data – UMTRI
2011—See Table A1.2. Tables—See Tables A1.12-A1.15.
TABLE A1.1 Scenario Numbers and Corresponding Data Tables for Each of the 36 Scenarios
Measurement
Performance
Scenario No. Sign Location Vehicle Type Letter Height Scenario No. Visual Complexity Angles and RA
Index Table
Multiplier Table
1 Right Shoulder Passenger Car 12 in. 1 Low/Medium Table A1.3 Table A1.12
2 2 High Table A1.3 Table A1.13
3 16 in. 3 Low/Medium Table A1.3 Table A1.14
4 4 High Table A1.3 Table A1.15
5 Light Truck/ SUV/ 12 in. 5 Low/Medium Table A1.6 Table A1.13
6 Minivan 6 High Table A1.6 Table A1.13
7 16 in. 7 Low/Medium Table A1.6 Table A1.14
8 8 High Table A1.6 Table A1.15
9 Heavy Vehicle 12 in. 9 Low/Medium Table A1.9 Table A1.12
10 10 High Table A1.9 Table A1.13
11 16 in. 11 Low/Medium Table A1.9 Table A1.14
12 12 High Table A1.9 Table A1.15
13 Overhead Passenger Car 12 in. 13 Low/Medium Table A1.4 Table A1.12
14 14 High Table A1.4 Table A1.13
15 16 in. 15 Low/Medium Table A1.4 Table A1.14
16 16 High Table A1.4 Table A1.15
17 Light Truck/ SUV/ 12 in. 17 Low/Medium Table A1.7 Table A1.12
18 Minivan 18 High Table A1.7 Table A1.13
19 16 in. 19 Low/Medium Table A1.7 Table A1.14
20 20 High Table A1.7 Table A1.15
21 Heavy Vehicle 12 in. 21 Low/Medium Table A1.10 Table A1.12
22 22 High Table A1.10 Table A1.13
23 16 in. 23 Low/Medium Table A1.10 Table A1.14
24 24 High Table A1.10 Table A1.15
25 Left Shoulder Passenger Car 12 in. 25 Low/Medium Table A1.5 Table A1.12
26 26 High Table A1.5 Table A1.13
27 16 in. 27 Low/Medium Table A1.5 Table A1.14
28 28 High Table A1.5 Table A1.15
29 Light Truck/ SUV/ 12 in. 29 Low/Medium Table A1.8 Table A1.12
30 Minivan 30 High Table A1.8 Table A1.13
31 16 in. 31 Low/Medium Table A1.8 Table A1.14
32 32 High Table A1.8 Table A1.15
33 Heavy Vehicle 12 in. 33 Low/Medium Table A1.11 Table A1.12
34 34 High Table A1.11 Table A1.13
35 16 in. 35 Low/Medium Table A1.11 Table A1.14
36 36 High Table A1.11 Table A1.15
D8379/D8379M−21
A
TABLE A1.2 Luminous Intensities (cd) for Sales-Weighted Sample Representing the Low-Beam Headlamps (Schoettle et al. (1))
8L 7.5L 7L 6.5L 6L 5.5L 5L 4.5L 4L 3.5L 3L 2.5L 2L 1.5L 1L 0.5L
5U 134.78 135.19 129.26 126.53 129.75 141.31 157.36 157.81 158.11 156.86 152.4 146.71 144.16 145.53 149.94 147.67
156.44 160.05 161.96 163.02 167.64 168.7 172.33 177.44 194 201.22 207.94 212.85 204.45 205.38 205.33 213.63
182 186.18 193.07 197.95 205.65 208.37 210.21 211.42 213.62 213.95 216.69 220.85 225.09 227.94 234.16 239.01
4.5U 164.81 168.52 170.43 170.37 166.45 170.55 173.05 172.44 173.78 173.81 175.75 180.28 185.1 187.04 195.05 197.31
208.03 213.11 219.2 223.28 229.79 231.99 231.43 232.39 238.15 239.81 238.13 242.71 247.17 247.2 247.33 248.01
256.76 258.66 254.51 254.62 255.07 265.33 268.92 269.58 272.23 268.75 270.85 259.15 276.73 280.08 273.95 279.58
4U 174.81 180.11 184.38 189.51 194.98 198.97 203.12 198.32 199.72 202.01 206.74 210.85 214.44 218.17 210.4 224.77
214.06 222.2 242.63 236.69 243.66 243.67 243.23 243.88 246.15 244.63 248.02 248.4 252.81 255.6 260.49 264.46
275.87 275.99 276.37 277.94 279.49 281.48 284.62 285.31 287.8 289.1 289.73 290.08 295.38 296.75 300.77 302.14
3.5U 193.17 197.43 212.92 208.42 216.77 226.99 226.27 227.43 226.96 224.2 228.73 232.27 256.46 264.62 253.19 248.99
258.51 267.17 278.03 285.38 292.74 289.06 282.13 282.11 289.99 292.64 290.31 298.71 283.59 288.76 297.33 302.04
281.12 288.18 304.32 315.74 310.45 313.83 321.03 327.36 338.08 342 341.24 343.53 346.91 352.22 369.27 388.56
3U 204.08 211.14 220.15 220.83 227.15 246.25 256.45 257.5 257.77 256.78 252.93 251.44 284.44 276.87 281.92 287.18
249.05 260.48 273.11 282.54 294.64 302.93 303.51 306.57 311.4 316.74 316.43 315.11 315.63 318.11 322.12 322.67
304.2 320.51 335.36 337.21 337.99 338.13 350.65 358.15 372.53 379.93 387.38 385.75 386.69 391.57 400.88 418
2.5U 208.48 216.28 234.33 241.67 262.77 272.08 281.69 285.75 292.29 294.66 314.49 312.77 336.51 322.4 317.88 320.51
241.54 246.14 255.82 266.77 288.66 299.62 316.39 326.4 336.23 358.1 351.66 355.65 357.6 361.93 376.85 386.27
325 357.09 366.66 375.05 389.09 393.91 403.63 411.48 428.01 438.4 453.64 467.29 481.26 489.82 451.2 470.8
2U 234.41 246.96 257.09 267.11 283.56 293.81 308.9 316.37 329.33 338.8 334.38 355.04 362.24 359.86 365.96 363.61
251.73 268.98 286.73 292.59 302 320.41 329.55 332.76 350.71 364.84 388.26 385.06 390.02 410.14 430.33 441.59
354.19 363.33 376.54 382.19 392.97 401.99 438.08 453.45 466.6 482.16 508.52 537.43 541.23 554.99 519.66 534.19
1.5U 250.85 262.44 282.61 297.35 319.12 327.26 344.11 358.09 375.14 378.47 395.7 397.53 401.72 405.99 414.35 416.49
269.31 280.81 301.16 312.72 329.9 342.39 360.66 371.17 416.96 412.45 414.86 450.9 470.57 510.52 523.37 541.8
367.59 383.39 382.84 393.69 411.32 423.84 443.41 481.83 499.32 529.69 542.83 550.19 550.05 548.33 584.88 593.91
1U 252.63 260.08 281.57 295.46 317.93 330.91 356.66 365.99 386.51 397.64 409.95 417.11 423.68 430.66 459.41 474.27
323.57 338.02 359.57 369.42 384.87 397.35 421.57 433.96 490.82 486.66 494.6 518.33 543.24 556.39 570.4 585.94
395.84 406.08 416.07 429.66 453.65 460.69 479.84 491.85 511.74 522.31 528.34 543.72 575.57 594.84 634.21 650.5
0.5U 269.96 282.33 306.32 320.58 343.15 357.84 375.9 389.48 408.34 416.33 433.01 446.49 470.44 488.77 547.1 602.61
392.03 407.47 423.11 436.79 472.96 518.42 555.79 600.27 655.74 665.56 669.95 681.17 767.24 831.02 896.35 936.72
714.24 722.7 735.47 744.46 768.55 785.4 794.47 814.86 861.11 880.19 919.65 979.5 998.53 1018.48 1003.04 1037.03
0 494.38 508.08 521.61 532.73 552.91 525.39 596.08 620.41 617.55 648.27 662.83 681.2 745.8 827.46 1048.35 1331.84
636.15 681.94 701.03 710.46 764.17 870.27 940.67 1091.67 1143.88 1207.79 1349.88 1380.68 1557.24 1821.9 2259.83 2461.44
1321.73 1379.34 1381.47 1405.99 1523.15 1622.43 1671.83 1708.28 1820.88 1982.43 2092.92 2136.9 2333.6 2429.22 2547.32 2856.78
0 0.5R 1R 1.5R 2R 2.5R 3R 3.5R 4R 4.5R 5R
5U 147.41 145.64 153.5 150.11 146.57 146.57 145.7 143.52 141.7 135.81 140.31
213.07 214.79 229.73 212.03 232 227.21 210.94 209.76 208.96 206.63 205.81
244.94 248.55 252.48 255.13 253.32 247.72 241.82 241.55 240.02 237.6 233.85
4.5U 198.45 195.34 196.85 198.05 197.97 194.94 192.66 190.13 185.49 192.08 185.41
247.87 248.58 252.66 261.73 263.77 262.69 261.68 256.06 254.65 254.35 251.72
281.05 282.38 286.48 287.8 284.8 284.37 289.42 290.66 299.28 291.89 283.45
4U 226.7 234.05 226.4 224.65 228.61 234.88 221.3 219.56 213.3 210.59 214.82
271.71 275.76 278.28 283.33 289.47 296.23 296.37 292.83 291.93 281.64 279.05
299.56 304.47 307.97 308.98 306.67 303 312.29 315.64 310.59 316.5 294.15
3.5U 253.16 254.4 251.69 249.55 246.65 244.24 245.88 249.27 242.91 238.23 240.48
301.12 300.05 300.45 299.72 307.92 312.53 319.47 324.67 317.72 312.99 295.75
391.44 393.75 386.19 384 380.16 370.54 355.86 349.11 358.32 355.75 341.79
3U 290.63 279.96 280.95 279.61 277.25 277.48 275.69 284.65 281.74 283.55 294.55
324.86 325.12 324.92 324.92 335.2 341.44 350.02 344.35 346.09 334.43 334.97
416.84 429.25 415.95 416.47 408.78 415.04 413.61 390.28 385.28 384.85 372.04
2.5U 321.66 324.48 333.65 328.08 340.03 347.62 342.33 362.44 320.12 314.24 311.76
378.07 380.84 386.49 397.19 422.66 434.41 455.49 415.71 432.87 396.5 398.38
479.06 486 477.59 475.81 464.38 463.36 464.07 461.91 445.3 450.05 436.77
2U 353.22 356.45 367.16 385.21 380.22 376.73 369.02 382.86 355.85 347.59 343.41
461.24 463.1 464.2 478.84 490.16 492.33 499 489.49 472.69 435.27 395.61
537.74 538.71 526.3 522.22 517.23 516.31 522.7 518.04 492.14 492.55 476.54
1.5U 413.49 414.27 433.77 459.59 452.26 441.05 420.13 409.98 404.82 387.11 389.08
578.88 603 596.12 582 566.65 557.6 544.53 541.42 536.62 532.63 493.81
623.75 617.84 626.7 641.21 641.52 654.31 656.91 624.64 586.45 560.27 535.83
1U 481.55 499.72 522.27 550.1 530.08 501.14 454.18 432.51 417.79 411.78 394.71
582.41 581.81 573.75 613.31 665.87 666.72 686.23 663.94 601.03 588.8 569.45
706.05 749.39 768.07 782.51 801.9 798.53 790.29 762.62 703.88 700.91 672.27
0.5U 697.4 820.9 944.75 949.74 899.63 826.67 699.69 659.37 615.59 596.56 592.68
1080.8 1126.06 1159.87 1215.91 1260.17 1218.75 1202.63 1116.59 1043.35 994.71 974.72
1152.14 1248.21 1339.02 1350.33 1355.3 1340.17 1294.67 1250 1120.97 1045.02 1017.38
0 2345.83 3214.88 3633.49 3661.13 3577.71 3486.11 2998.84 2728.16 2408.25 2241.42 2135.89
3092.23 3612.98 4164.56 4175.91 3945.28 4142.89 4001.46 3942.72 3460.95 3132.11 2840.49
3328.71 3919.65 4399.75 4493.22 4533.93 4572.18 4370.71 4205.19 3928.92 3789.8 3265.03
A th th th
Each cell contains 25 ,50 , and 75 percentile, from top to bottom, respectively.
D8379/D8379M−21
TABLE A1.3 α, β , β , ε Angles (deg) and R Multipliers for Passenger Car, Right Shoulder (PC-RS) Sign Scenarios (Scenarios 1–4)
1 2 A
LEFT HEADLIGHT RIGHT HEADLIGHT
Dist. to Dist. to
Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult. Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult.
A A A A A A
Sign Sign
Angle Angle Angle Angle (25 %) (50 %) (75 %) Angle Angle Angle Angle (25 %) (50 %) (75 %)
(ft) (m)
α β β ε (lx) (lx) (lx) α β β ε (lx) (lx) (lx)
1 2 1 2
640 195.07 0.18 2.81 4.90 24.35 0.0170 0.0220 0.0245 0.27 -3.93 3.64 -53.09 0.0172 0.0214 0.0244
630 192.02 0.18 2.83 4.91 24.41 0.0173 0.0225 0.0251 0.28 -3.93 3.66 -53.05 0.0175 0.0219 0.0249
620 188.98 0.19 2.86 4.93 24.48 0.0177 0.0230 0.0256 0.28 -3.94 3.68 -53.01 0.0179 0.0223 0.0255
610 185.93 0.19 2.88 4.95 24.54 0.0180 0.0235 0.0262 0.29 -3.95 3.71 -52.97 0.0184 0.0228 0.0261
600 182.88 0.19 2.91 4.97 24.61 0.0184 0.0240 0.0268 0.29 -3.96 3.73 -52.92 0.0188 0.0234 0.0267
590 179.83 0.20 2.93 4.98 24.69 0.0188 0.0246 0.0275 0.30 -3.97 3.76 -52.88 0.0192 0.0239 0.0274
580 176.78 0.20 2.96 5.00 24.76 0.0192 0.0252 0.0281 0.30 -3.98 3.78 -52.83 0.0197 0.0244 0.0280
570 173.74 0.20 2.99 5.02 24.84 0.0195 0.0258 0.0288 0.31 -3.99 3.81 -52.78 0.0202 0.0250 0.0287
560 170.69 0.21 3.02 5.04 24.92 0.0200 0.0264 0.0295 0.31 -4.01 3.84 -52.73 0.0206 0.0256 0.0294
550 167.64 0.21 3.05 5.07 25.00 0.0204 0.0271 0.0303 0.32 -4.02 3.87 -52.68 0.0211 0.0262 0.0301
540 164.59 0.22 3.09 5.09 25.09 0.0208 0.0278 0.0311 0.32 -4.03 3.90 -52.62 0.0215 0.0268 0.0309
530 161.54 0.22 3.12 5.11 25.18 0.0212 0.0285 0.0318 0.33 -4.04 3.93 -52.56 0.0220 0.0275 0.0316
520 158.50 0.23 3.16 5.13 25.27 0.0217 0.0292 0.0327 0.33 -4.05 3.96 -52.50 0.0225 0.0282 0.0324
510 155.45 0.23 3.19 5.16 25.36 0.0221 0.0299 0.0335 0.34 -4.07 4.00 -52.44 0.0230 0.0289 0.0333
500 152.40 0.24 3.23 5.18 25.46 0.0226 0.0305 0.0343 0.35 -4.08 4.03 -52.38 0.0235 0.0296 0.0341
490 149.35 0.24 3.27 5.21 25.56 0.0230 0.0311 0.0352 0.35 -4.09 4.07 -52.31 0.0240 0.0303 0.0350
480 146.30 0.25 3.31 5.24 25.67 0.0235 0.0318 0.0361 0.36 -4.11 4.11 -52.24 0.0245 0.0311 0.0360
470 143.26 0.25 3.36 5.27 25.78 0.0239 0.0325 0.0370 0.37 -4.12 4.15 -52.17 0.0251 0.0320 0.0369
460 140.21 0.26 3.40 5.29 25.89 0.0244 0.0332 0.0380 0.38 -4.14 4.19 -52.09 0.0256 0.0328 0.0380
450 137.16 0.26 3.45 5.33 26.01 0.0249 0.0339 0.0390 0.38 -4.15 4.24 -52.01 0.0262 0.0337 0.0390
440 134.11 0.27 3.50 5.36 26.13 0.0254 0.0347 0.0400 0.39 -4.17 4.28 -51.93 0.0268 0.0347 0.0401
430 131.06 0.28 3.55 5.39 26.26 0.0259 0.0355 0.0411 0.40 -4.19 4.33 -51.84 0.0274 0.0357 0.0413
420 128.02 0.28 3.61 5.42 26.40 0.0264 0.0363 0.0422 0.41 -4.20 4.38 -51.75 0.0280 0.0366 0.0424
410 124.97 0.29 3.67 5.46 26.54 0.0269 0.0371 0.0433 0.42 -4.22 4.44 -51.65 0.0286 0.0374 0.0436
400 121.92 0.30 3.73 5.50 26.69 0.0273 0.0381 0.0444 0.43 -4.24 4.49 -51.55 0.0292 0.0382 0.0447
390 118.87 0.31 3.79 5.54 26.84 0.0277 0.0392 0.0455 0.44 -4.26 4.55 -51.44 0.0298 0.0391 0.0459
380 115.82 0.32 3.86 5.58 27.00 0.0281 0.0402 0.0467 0.45 -4.28 4.61 -51.33 0.0305 0.0400 0.0472
370 112.78 0.33 3.93 5.62 27.17 0.0285 0.0414 0.0480 0.46 -4.30 4.68 -51.21 0.0311 0.0409 0.0485
360 109.73 0.34 4.01 5.67 27.34 0.0289 0.0426 0.0493 0.47 -4.33 4.75 -51.08 0.0317 0.0418 0.0498
350 106.68 0.35 4.09 5.71 27.53 0.0293 0.0439 0.0506 0.49 -4.35 4.82 -50.94 0.0324 0.0428 0.0512
340 103.63 0.36 4.17 5.76 27.73 0.0304 0.0456 0.0526 0.50 -4.37 4.90 -50.80 0.0336 0.0446 0.0533
330 100.58 0.37 4.26 5.82 27.93 0.0318 0.0475 0.0549 0.51 -4.40 4.99 -50.65 0.0350 0.0469 0.0559
320 97.54 0.38 4.36 5.87 28.15 0.0334 0.0495 0.0572 0.53 -4.43 5.07 -50.49 0.0364 0.0495 0.0586
310 94.49 0.40 4.46 5.93 28.38 0.0351 0.0517 0.0597 0.54 -4.45 5.17 -50.31 0.0379 0.0522 0.0615
300 91.44 0.41 4.57 5.99 28.62 0.0370 0.0540 0.0622 0.56 -4.48 5.27 -50.13 0.0395 0.0550 0.0647
290 88.39 0.43 4.69 6.05 28.88 0.0391 0.0563 0.0647 0.58 -4.51 5.38 -49.93 0.0414 0.0579 0.0681
280 85.34 0.44 4.82 6.12 29.15 0.0415 0.0585 0.0670 0.60 -4.54 5.50 -49.72 0.0434 0.0610 0.0718
270 82.30 0.46 4.96 6.19 29.44 0.0441 0.0612 0.0694 0.62 -4.57 5.62 -49.49 0.0460 0.0640 0.0751
260 79.25 0.48 5.11 6.27 29.75 0.0471 0.0643 0.0720 0.64 -4.61 5.76 -49.24 0.0489 0.0672 0.0787
250 76.20 0.50 5.27 6.35 30.07 0.0503 0.0683 0.0754 0.66 -4.64 5.91 -48.97 0.0521 0.0709 0.0824
240 73.15 0.53 5.44 6.44 30.43 0.0535 0.0730 0.0789 0.69 -4.68 6.07 -48.67 0.0558 0.0748 0.0861
D8379/D8379M−21
TABLE A1.4 α, β , β , ε Angles for Passenger Car, Overhead (PC-OH) Sign Scenarios (Scenarios 13–16)
1 2
LEFT HEADLIGHT RIGHT HEADLIGHT
Dist. to Dist. to
Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult. Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult.
A A A A A A
Sign Sign
Angle Angle Angle Angle (25 %) (50 %) (75 %) Angle Angle Angle Angle (25 %) (50 %) (75 %)
(ft) (m)
α β β ε (lx) (lx) (lx) α β β ε (lx) (lx) (lx)
1 2 1 2
640 195.07 0.19 5.47 -1.68 18.52 0.0073 0.0100 0.0111 0.29 3.58 4.47 -52.73 0.0074 0.0098 0.0110
630 192.02 0.19 5.49 -1.69 18.50 0.0075 0.0102 0.0114 0.30 3.60 4.48 -52.69 0.0075 0.0099 0.0113
620 188.98 0.19 5.52 -1.69 18.48 0.0077 0.0104 0.0116 0.30 3.62 4.50 -52.65 0.0077 0.0101 0.0116
610 185.93 0.20 5.55 -1.70 18.45 0.0079 0.0106 0.0119 0.31 3.64 4.52 -52.60 0.0079 0.0103 0.0118
600 182.88 0.20 5.58 -1.70 18.43 0.0081 0.0108 0.0122 0.31 3.67 4.54 -52.56 0.0081 0.0105 0.0121
590 179.83 0.20 5.61 -1.71 18.41 0.0083 0.0110 0.0125 0.32 3.69 4.56 -52.51 0.0083 0.0108 0.0124
580 176.78 0.21 5.64 -1.71 18.39 0.0085 0.0112 0.0128 0.32 3.72 4.58 -52.46 0.0085 0.0111 0.0128
570 173.74 0.21 5.68 -1.72 18.36 0.0087 0.0115 0.0132 0.33 3.74 4.60 -52.41 0.0087 0.0113 0.0131
560 170.69 0.22 5.71 -1.72 18.34 0.0089 0.0117 0.0135 0.34 3.77 4.63 -52.36 0.0089 0.0115 0.0134
550 167.64 0.22 5.75 -1.73 18.31 0.0091 0.0119 0.0138 0.34 3.80 4.65 -52.31 0.0092 0.0117 0.0138
540 164.59 0.22 5.78 -1.73 18.28 0.0094 0.0122 0.0142 0.35 3.83 4.67 -52.25 0.0094 0.0120 0.0142
530 161.54 0.23 5.82 -1.74 18.25 0.0097 0.0125 0.0147 0.36 3.86 4.70 -52.20 0.0097 0.0123 0.0146
520 158.50 0.23 5.86 -1.75 18.23 0.0100 0.0127 0.0151 0.36 3.89 4.72 -52.14 0.0100 0.0126 0.0150
510 155.45 0.24 5.90 -1.75 18.20 0.0103 0.0129 0.0156 0.37 3.92 4.75 -52.08 0.0103 0.0129 0.0155
500 152.40 0.24 5.95 -1.76 18.17 0.0106 0.0133 0.0160 0.38 3.96 4.78 -52.01 0.0107 0.0132 0.0159
490 149.35 0.25 5.99 -1.77 18.13 0.0110 0.0136 0.0165 0.39 3.99 4.81 -51.95 0.0110 0.0135 0.0164
480 146.30 0.26 6.04 -1.77 18.10 0.0113 0.0139 0.0170 0.40 4.03 4.84 -51.88 0.0113 0.0138 0.0169
470 143.26 0.26 6.09 -1.78 18.07 0.0117 0.0142 0.0176 0.40 4.07 4.87 -51.81 0.0117 0.0143 0.0174
460 140.21 0.27 6.14 -1.79 18.03 0.0121 0.0145 0.0182 0.41 4.11 4.90 -51.73 0.0121 0.0146 0.0180
450 137.16 0.27 6.19 -1.80 17.99 0.0125 0.0149 0.0188 0.42 4.16 4.93 -51.65 0.0125 0.0150 0.0185
440 134.11 0.28 6.25 -1.81 17.95 0.0130 0.0153 0.0194 0.43 4.20 4.97 -51.57 0.0129 0.0153 0.0191
430 131.06 0.29 6.30 -1.82 17.91 0.0134 0.0157 0.0200 0.44 4.25 5.00 -51.49 0.0134 0.0158 0.0197
420 128.02 0.30 6.36 -1.82 17.87 0.0138 0.0162 0.0206 0.45 4.30 5.04 -51.40 0.0138 0.0162 0.0203
410 124.97 0.30 6.43 -1.83 17.83 0.0143 0.0167 0.0213 0.47 4.35 5.08 -51.31 0.0143 0.0166 0.0210
400 121.92 0.31 6.50 -1.84 17.78 0.0148 0.0170 0.0220 0.48 4.40 5.12 -51.21 0.0148 0.0171 0.0217
390 118.87 0.32 6.57 -1.86 17.74 0.0153 0.0176 0.0227 0.49 4.46 5.17 -51.11 0.0154 0.0176 0.0224
380 115.82 0.33 6.64 -1.87 17.69 0.0158 0.0182 0.0235 0.50 4.52 5.21 -51.00 0.0159 0.0181 0.0231
370 112.78 0.34 6.72 -1.88 17.63 0.0163 0.0187 0.0242 0.52 4.59 5.26 -50.89 0.0165 0.0186 0.0239
360 109.73 0.35 6.80 -1.89 17.58 0.0169 0.0194 0.0252 0.53 4.66 5.31 -50.77 0.0171 0.0193 0.0249
350 106.68 0.36 6.89 -1.90 17.52 0.0175 0.0202 0.0263 0.55 4.73 5.36 -50.65 0.0176 0.0202 0.0260
340 103.63 0.38 6.98 -1.92 17.46 0.0182 0.0211 0.0275 0.57 4.80 5.42 -50.52 0.0182 0.0211 0.0272
330 100.58 0.39 7.08 -1.93 17.40 0.0189 0.0221 0.0288 0.58 4.89 5.48 -50.38 0.0188 0.0221 0.0285
320 97.54 0.40 7.18 -1.94 17.33 0.0196 0.0231 0.0302 0.60 4.97 5.54 -50.24 0.0194 0.0231 0.0299
310 94.49 0.42 7.29 -1.96 17.26 0.0204 0.0241 0.0311 0.62 5.06 5.60 -50.08 0.0201 0.0242 0.0309
300 91.44 0.43 7.41 -1.98 17.19 0.0213 0.0252 0.0312 0.65 5.16 5.67 -49.92 0.0209 0.0251 0.0310
290 88.39 0.45 7.54 -1.99 17.11 0.0223 0.0264 0.0313 0.67 5.27 5.75 -49.74 0.0218 0.0261 0.0311
280 85.34 0.47 7.67 -2.01 17.03 0.0233 0.0276 0.0313 0.70 5.38 5.83 -49.56 0.0227 0.0270 0.0311
270 82.30 0.49 7.82 -2.03 16.94 0.0242 0.0289 0.0320 0.72 5.51 5.91 -49.36 0.0236 0.0282 0.0318
260 79.25 0.51 7.97 -2.05 16.85 0.0248 0.0303 0.0338 0.75 5.64 6.00 -49.15 0.0245 0.0297 0.0336
250 76.20 0.54 8.14 -2.07 16.75 0.0253 0.0316 0.0357 0.78 5.79 6.10 -48.92 0.0253 0.0314 0.0354
240 73.15 0.56 8.32 -2.10 16.65 0.0254 0.0329 0.0374 0.82 5.94 6.20 -48.68 0.0256 0.0328 0.0370
D8379/D8379M−21
TABLE A1.5 α, β , β , ε Angles (deg) and R Multipliers for Passenger Car, Left Shoulder (PC-LS) Sign Scenarios (Scenarios 25–28)
1 2 A
LEFT HEADLIGHT RIGHT HEADLIGHT
Dist. to Dist. to
Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult. Obs. Ent. Ent. Rot. R Mult. R Mult. R Mult.
A A A A A A
Sign Sign
Angle Angle Angle Angle (25 %) (50 %) (75 %) Angle Angle Angle Angle (25 %) (50 %) (75 %)
(ft) (m)
α β β ε (lx) (lx) (lx) α β β ε (lx) (lx) (lx)
1 2 1 2
640 195.07 0.17 -0.74 -6.48 11.28 0.0084 0.0127 0.0177 0.31 6.03 -3.17 -57.75 0.0083 0.0125 0.0171
630 192.02 0.17 -0.72 -6.52 11.14 0.0087 0.0130 0.0180 0.31 6.07 -3.19 -57.78 0.0085 0.0128 0.0174
620 188.98 0.17 -0.70 -6.56 11.00 0.0089 0.0133 0.0183 0.32 6.12 -3.20 -57.81 0.0088 0.0131 0.0177
610 185.93 0.18 -0.68 -6.61 10.85 0.0092 0.0137 0.0186 0.32 6.16 -3.21 -57.85 0.0090 0.0135 0.0180
600 182.88 0.18 -0.66 -6.65 10.69 0.0095 0.0140 0.0189 0.33 6.21 -3.23 -57.88 0.0093 0.0138 0.0183
590 179.83 0.18 -0.64 -6.70 10.53 0.0098 0.0144 0.0193 0.34 6.26 -3.24 -57.92 0.0096 0.0142 0.0186
580 176.78 0.19 -0.62 -6.75 10.37 0.0101 0.0148 0.0196 0.34 6.31 -3.26 -57.95 0.0099 0.0146 0.0190
570 173.74 0.19 -0.60 -6.80 10.20 0.0104 0.0152 0.0200 0.35 6.37 -3.27 -57.99 0.0101 0.0150 0.0193
560 170.69 0.19 -0.58 -6.85 10.02 0.0107 0.0156 0.0203 0.36 6.42 -3.29 -58.03 0.0105 0.0154 0.0197
550 167.64 0.20 -0.55 -6.91 9.84 0.0110 0.0160 0.0207 0.36 6.48 -3.31 -58.07 0.0108 0.0158 0.0201
540 164.59 0.20 -0.53 -6.97 9.65 0.0114 0.0164 0.0211 0.37 6.54 -3.32 -58.11 0.0111 0.0163 0.0205
530 161.54 0.20 -0.50 -7.02 9.45 0.0118 0.0169 0.0214 0.38 6.60 -3.34 -58.16 0.0115 0.0168 0.0209
520 158.50 0.21 -0.47 -7.09 9.25 0.0122 0.0174 0.0219 0.39 6.66 -3.36 -58.20 0.0119 0.0173 0.0214
510 155.45 0.21 -0.44 -7.15 9.03 0.0126 0.0179 0.0223 0.39 6.73 -3.38 -58.25 0.0123 0.0178 0.0218
500 152.40 0.22 -0.41 -7.21 8.81 0.0130 0.0185 0.0228 0.40 6.80 -3.40 -58.30 0.0127 0.0183 0.0223
490 149.35 0.22 -0.38 -7.28 8.58 0.0135 0.0190 0.0233 0.41 6.87 -3.42 -58.35 0.0132 0.0189 0.0228
480 146.30 0.22 -0.34 -7.35 8.34 0.0140 0.
...