National Standards for Traffic Control Devices; the Manual on Uniform Traffic Control Devices for Streets and Highways; Maintaining Traffic Sign Retroreflectivity, 26711-26721 [E6-6882]

Agencies

• Federal Highway Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 88 (Monday, May 8, 2006)]
[Proposed Rules]
[Pages 26711-26721]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-6882]


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DEPARTMENT OF TRANSPORTATION

Federal Highway Administration

23 CFR Part 655

[FHWA Docket No. FHWA-2003-15149]
RIN 2125-AE98


National Standards for Traffic Control Devices; the Manual on 
Uniform Traffic Control Devices for Streets and Highways; Maintaining 
Traffic Sign Retroreflectivity

AGENCY: Federal Highway Administration (FHWA), (DOT).

ACTION: Supplemental notice of proposed amendments (SNPA); request for 
comments.

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SUMMARY: In an earlier notice of proposed amendments (NPA), the FHWA 
proposed to amend the Manual on Uniform Traffic Control Devices for 
Streets and Highways (MUTCD) to include methods to maintain traffic 
sign retroreflectivity. Based on the review and analysis of the 
numerous comments received in response to the NPA, the FHWA has decided 
to substantially revise the proposed amendments to the MUTCD and, as a 
result, is issuing this SNPA. With this SNPA, the FHWA proposes to 
amend the MUTCD to include a standard for minimum maintained levels of 
traffic sign retroreflectivity and methods to maintain traffic sign 
retroreflectivity at or above these levels.

DATES: Comments must be received on or before November 6, 2006.

ADDRESSES: Mail or hand deliver comments to the U.S. Department of 
Transportation, Dockets Management Facility, Room PL-401, 400 Seventh 
Street, SW., Washington, DC 20590, or submit electronically at https://
dms.dot.gov or fax comments to (202) 493-2251. Alternatively, comments 
may be submitted via the Federal eRulemaking Portal at https://
www.regulations.gov. All comments should include the docket number that 
appears in the heading of this document. All comments received will be 
available for examination and copying at the above address from 9 a.m. 
to 5 p.m., e.t., Monday through Friday, except Federal holidays. Those 
desiring notification of receipt of comments must include a self-
addressed, stamped postcard or may print the acknowledgment page that 
appears after submitting comments electronically. Anyone is able to 
search the electronic form of all comments received into any of our 
dockets by the name of the individual submitting the comment (or 
signing the comment, if submitted on behalf of an association, 
business, labor union, etc.). Persons making comments may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70, Pages 19477-78) or may visit 
https://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Ms. Debra Chappell, Office of Safety 
Design (202) 366-0087, or Raymond Cuprill, Office of the Chief Counsel 
(202) 366-0791, Federal Highway Administration, 400 Seventh Street, 
SW., Washington, DC 20590-0001. Office hours are from 7:45 a.m. to 4:15 
p.m., e.t., Monday through Friday, except Federal holidays.

SUPPLEMENTARY INFORMATION: 

Electronic Access and Filing

    Interested parties may submit or retrieve comments online through 
the Document Management System (DMS) at https://dms.dot.gov. The DMS is 
available 24 hours each day, 365 days each year. Electronic submission, 
retrieval help, and guidelines are available under the help section of 
the Web site.
    An electronic copy of this document may be downloaded using the 
Office of the Federal Register's home page at https://www.archives.gov 
and the Government Printing Office's Web page at https://
www.access.gpo.gov/nara.

Background

    On July 30, 2004, at 69 FR 45623, the FHWA published in the Federal 
Register an NPA to amend the MUTCD to include methods to maintain 
traffic sign retroreflectivity.1 2 This NPA was in response 
to a Congressional directive in the Department of Transportation and 
Related Agencies Appropriations Act, 1993 (Pub. L. 102-388; October 6, 
1992). Section 406 of this Act directed the Secretary of Transportation 
to revise the MUTCD to include a standard for minimum levels of 
retroreflectivity that must be maintained for traffic signs and 
pavement markings, which apply to all roads open to public travel. The 
FHWA is currently conducting research to develop a standard for minimum 
levels of pavement marking retroreflectivity. However, a NPA regarding 
minimum pavement marking retroreflectivity is not expected to be issued 
until the rulemaking for minimum traffic sign retroreflectivity is 
finalized.
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    \1\ The NPA published on July 30, 2004, at 69 FR 45623, 
describes the research and development and other efforts by the FHWA 
to implement this requirement. More information is available at the 
following Web address: https://www.fhwa.dot.gov/retro.
    \2\ The definition and measurement of retroreflectivity are 
described in the International Commission on Illumination's report, 
``Retroreflection: Definition and Measurement'' CIE Publication 
54.2-2001, CIE Central Bureau, Vienna, Austria. The document is 
available at the following Web address: https://www. cie.co.at/ 
framepublications.html.
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    The comment period for the NPA initially expired on October 28, 
2004, but was extended to February 1, 2005 (69 FR 62007). As of June 1, 
2005, the FHWA received 85 letters submitted to the docket containing 
350 individual comments on the NPA. The FHWA received comments from the 
National Committee on Uniform Traffic Control Devices (NCUTCD), the 
American Association of State Highway and Transportation Officials 
(AASHTO), State Departments of Transportation (State DOTs), city and 
county governmental agencies, consulting firms, private industry, 
associations, other organizations, and individual private citizens. The 
FHWA has reviewed and analyzed the comments that were received as of 
June 1, 2005. Docket comments and summaries of the FHWA's analyses and 
determinations are discussed below. After considering and analyzing the 
comments, the FHWA has decided to issue this SNPA. The proposed changes 
would be designated as Revision No. 2 to the 2003 Edition of the 
MUTCD.\3\
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    \3\ The proposed changes to the MUTCD are available for review 
at the following Web address: https://tcd.tamu.edu/Documents/
MinRetro/2005-08-02_PROPOSED_Rev2.pdf.
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    The MUTCD is incorporated by reference in 23 CFR 655.601. It is 
available for inspection and copying as prescribed in 49 CFR part 7 and 
on the FHWA's Web site at https://mutcd.fhwa.dot.gov. Requirements for 
nighttime sign visibility have been included in every version of the

[[Page 26712]]

MUTCD since the first edition in 1935. The 2003 Edition of the MUTCD 
continues to address the visibility of signs. Two pertinent MUTCD 
sections include: Section 2A.08 Retroreflectivity and Illumination, 
which states, ``[r]egulatory, warning, and guide signs shall be 
retroreflective or illuminated to show the same shape and similar color 
by both day and night, unless specifically stated otherwise in the text 
discussion in this Manual of a particular sign or group of signs'' and 
Section 2A.22 Maintenance, which states, ``All traffic signs should be 
kept properly positioned, clean, and legible, and should have adequate 
retroreflectivity.'' Section 2A.22 also recommends that nighttime 
inspections be scheduled to assure adequate sign maintenance. This SNPA 
proposes MUTCD revisions that address minimum sign retroreflectivity 
levels and methods to maintain sign retroreflectivity. The proposed 
MUTCD revisions would be mostly included in Section 2A.09 Minimum 
Retroreflectivity Levels, which was a new section added in the MUTCD 
Millennium Edition. Section 2A.09 currently serves as a placeholder for 
the results of this SNPA.
    While many of the respondents agreed with the intent and the 
concepts proposed in the NPA, there were other respondents that 
provided comments related to the following five major issues:
    (1) The NPA proposal did not meet the intent of the 1993 
Congressional directive to include a standard for the minimum levels of 
retroreflectivity for traffic signs in the MUTCD;
    (2) The table outlining the minimum retroreflectivity levels should 
be placed in the MUTCD;
    (3) Further clarification of the compliance period should be 
provided;
    (4) The visibility impacts associated with maintained sign 
retroreflectivity should be described; and
    (5) The requirements in the proposal would impose additional time 
and resource burdens on public agencies.
    The FHWA has decided to address the issues raised by the 
respondents by issuing this SNPA. The purpose of this SNPA is to obtain 
public comment on revised proposed amendments to the MUTCD to include a 
standard for minimum levels of retroreflectivity that must be 
maintained for traffic signs and methods to maintain traffic sign 
retroreflectivity at or above these levels. The FHWA proposes the 
following key changes:
    (1) Add a STANDARD statement to Section 2A.09 that reads, ``Public 
agencies or officials having jurisdiction shall use an assessment or 
management method to maintain traffic sign retroreflectivity at or 
above the minimum levels established in the Guidance below.'' This 
STANDARD statement requires that a method be used to manage and 
maintain retroreflectivity and also requires that sign 
retroreflectivity be maintained to minimum levels. This is a revised 
version of the GUIDANCE statement that was proposed in the NPA.
    (2) Include the table of minimum retroreflectivity levels in the 
MUTCD. In the NPA, the table of retroreflectivity levels was not 
included in the MUTCD, but was instead contained in a document that was 
referenced in the MUTCD.
    These proposed changes are significant enough to warrant a SNPA, 
which will also allow the FHWA to obtain and assess additional public 
comments, including comments from States and local governments, before 
a final rule is issued.

Discussion of Major Issues

    This section provides a discussion of each of the five major issues 
for which comments were received in response to the NPA, along with the 
FHWA's proposed resolution. The next section discusses additional 
comments that were received in response to the NPA that were not 
related to the five major issues.
    (1) The NPA proposal did not meet the intent of the 1993 
Congressional directive to include a standard for the minimum levels of 
retroreflectivity for traffic signs in the MUTCD.
    The FHWA received comments from the National Association of County 
Engineers (NACE), New Jersey DOT, Saline County (Kansas), and the City 
of Plano (Texas) supporting the proposed text in the NPA that proposed 
to include the minimum retroreflectivity levels in a GUIDANCE 
statement, rather than a STANDARD statement.\4\ The Connecticut DOT 
opposed the proposed GUIDANCE, stating that by proposing to reference 
the minimum retroreflectivity levels and including compliance dates, 
the FHWA went beyond GUIDANCE.
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    \4\ In the context of this SNPA, the definitions of STANDARD and 
GUIDANCE are identical to the definitions provided in the 
Introduction of the MUTCD (https://mutcd.fhwa.dot.gov). Specifically, 
a STANDARD is a statement of required, mandatory, or specifically 
prohibitive practice regarding a traffic control device while a 
GUIDANCE is a statement of recommended, but not mandatory, practice 
in typical situations, with deviations allowed if engineering 
judgment or engineering study indicates the deviation to be 
appropriate.
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    The American Automobile Association (AAA), the American Traffic 
Safety Services Association (ATSSA), the Advocates for Highway and Auto 
Safety (AHAS), the American Highway Users Alliance (AHUA), the American 
Association of Retired Persons (AARP), a representative of the sign 
industry, a consultant, and a private citizen all opposed the inclusion 
of minimum retroreflectivity as a GUIDANCE, and instead proposed that 
it should be a STANDARD. These comments stated that the Congressional 
intent was that the MUTCD should include a STANDARD, and that the 
importance of road safety is such that minimum levels of sign 
retroreflectivity should be emphasized by creating a STANDARD.
    The County Engineers Association of Illinois--District 3 submitted 
three comments in general opposition to the proposed changes. In 
particular, it felt that the proposed changes represented 
overregulation and could be written as simple guidelines that would not 
expose agencies to additional tort liability. McLean County (Illinois) 
also opposed the proposed changes because it takes pride in its work 
and states that a faded sign has never been blamed for a crash in 
McLean County.
    Considering these comments in conjunction with the FHWA's strong 
support for safety and the MUTCD's opening sentence regarding the use 
of traffic control devices to promote highway safety, the FHWA decided 
to propose a STANDARD statement that requires public agencies and 
officials with jurisdiction to implement a method to maintain traffic 
sign retroreflectivity at or above the minimum levels included in the 
MUTCD. This proposed STANDARD is intended to clearly satisfy the 
Congressional directive of the 1993 Appropriations Act as well as 
contribute to the improved safety of the motoring public. The FHWA 
acknowledges that many agencies and public officials might have 
concerns regarding this proposed STANDARD, particularly because of a 
perceived potential increase in tort litigation. However, the FHWA's 
primary concern is safety, and the FHWA believes this proposed change 
will promote safety on our nation's streets and highways. At the same 
time, the FHWA believes that the proposed changes to the MUTCD provide 
sufficient flexibility for the agencies or officials to choose a 
reasonable method to maintain and assess sign retroreflectivity that 
fits the particular circumstances in their jurisdictions. In fact, the 
selection of a reasonable method for maintaining sign retroreflectivity 
and strict adherence to the same might have the opposite effect 
concerning tort liability and litigation. Public agencies and officials 
that

[[Page 26713]]

implement and follow a reasonable method in conformance with the 
national MUTCD would appear to be in a better position to successfully 
defend tort litigation involving improper sign retroreflectivity than 
jurisdictions that lack any method.
    The proposed changes include five methods that agencies can use to 
maintain traffic sign retroreflectivity at or above the minimum levels. 
In addition, agencies are not limited to these five proposed methods, 
as they can also develop their own methods using documented engineering 
judgment or studies that demonstrate that deviations are 
appropriate.\5\ The FHWA's intent is that by using one of these 
proposed methods to assess and maintain traffic sign retroreflectivity, 
agencies would be in conformance with the national MUTCD requirement to 
maintain the minimum levels of traffic sign retroreflectivity.
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    \5\ The 2003 Edition of the MUTCD defines a guidance statement, 
which is how the five methods to maintain sign retroreflectivity are 
proposed in the SNPA, as a statement of recommended, but not 
mandatory, practice in typical situations, with deviations allowed 
if engineering judgment or engineering study indicates the deviation 
to be appropriate. The terms engineering judgment and engineering 
study are further defined in the MUTCD, which can be found online at 
the following URL: https://mutcd.fhwa.dot.gov.
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    The purpose of providing the five methods and allowing additional 
methods is to provide flexibility for agencies in terms of complying 
with the MUTCD. In other words, conformance with the proposed changes 
in this SNPA would be achieved by having a method in place to maintain 
the minimum retroreflectivity levels, rather than by providing the 
minimum retroreflectivity level for every individual sign at every 
point in time. For example, if an agency chooses to implement the 
visual nighttime inspection method, there is no guarantee that the 
retroreflectivity of all of the agency's signs listed in the table of 
minimum retroreflectivity levels will be satisfied during the entire 
period that the signs are in the field. Assuming that an agency 
successfully completes the annual visual nighttime inspections and that 
signs failing the subjective evaluation or signs rated as marginal are 
scheduled for replacement or reassessment within a reasonable time 
period, then there is clearly a period when these signs might be below 
the levels in the table of minimum retroreflectivity levels while the 
sign is awaiting replacement or reassessment. Having a method in place 
to maintain the minimum retroreflectivity levels is a valuable way for 
agencies to prioritize how to spend limited resources on those signs 
that should be replaced sooner, thus ultimately contributing to 
improved safety for the motoring public.
    There are other conditions where signs might be rated as being 
satisfactory while temporarily falling below the minimum 
retroreflectivity levels.\6\ For example, dew and frost on signs have 
been shown to significantly reduce retroreflectivity. In addition, 
while research has shown that the visual nighttime inspection is a 
reasonable method in terms of identifying signs that need to be 
replaced because of inadequate retroreflectivity, the nighttime visual 
inspection method is not 100 percent reliable.7 8 When 
inventories are not available for use on nighttime visual inspections, 
it is not unreasonable to miss a small percentage of signs along a 
densely-signed corridor, especially if a sign was knocked down or 
missing for some other reason at the time of the inspection. It is also 
possible that a sign or a group of signs could have adequate 
retroreflectivity for a predetermined number of years, but because of 
factors such as sign manufacturing defects or inadvertent mishandling 
during installation, a certain percentage might fall below the criteria 
in the proposed table of minimum retroreflectivity sooner than 
expected.
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    \6\ Hildebrand, E. Reduction in Traffic Sign Retroreflectivity 
Caused by Dew and Frost. Proceedings from Transportation Research 
Board's (TRB) 82nd Annual Meeting, Washington, DC, January 2003.
    \7\ Lagergran, E.A. Traffic Sign Retroreflectivity Measurements 
Using Human Observers. Report No. WA-RD-140.1, Washington State 
Transportation Center, Seattle, WA, 1987.
    \8\ Hawkins, H.G. and P.J. Carlson. Results of Visual 
Evaluations of Sign Retroreflectivity Compared with Minimum 
Retroreflectivity Recommendations. In Transportation Research Record 
1754, TRB, National Research Council, Washington, DC, 2001, pp. 11-
20.
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    Having records to document the methods for managing sign 
retroreflectivity will help the agency achieve conformance with the 
proposed standard to maintain the minimum levels of retroreflectivity 
of traffic signs, as well as provide the agency with a more systematic 
process of replacing signs and a better justification for the 
allocation of limited resources. For example, it would be reasonable to 
have documentation showing that nighttime sign inspections were 
conducted and that signs rated poor or marginal were marked for 
replacement or further evaluation. It would also be reasonable to have 
documentation showing the installation date of signs, their expected 
sign life, and programmed date of replacement. This is particularly 
important because measurements of traffic sign retroreflectivity might 
show that certain signs are near or below the thresholds in the table 
of minimum retroreflectivity levels before they reach their expected 
life. As long as an agency has a reasonable method in place to manage 
or assess its signs, and establishes a reasonable schedule for sign 
replacement as needed, then the agency will be deemed to be in 
conformance with the standard proposed in this SNPA.
    (2) The table outlining the minimum retroreflectivity levels should 
be placed in the MUTCD.
    The FHWA received many comments regarding the proposal in the NPA 
to place the table outlining the minimum maintained retroreflectivity 
levels in a referenced document (Maintaining Traffic Sign 
Retroreflectivity), rather than in the language of the MUTCD. On one 
hand, the FHWA received 30 comments representing the AASHTO, the NACE, 
26 State DOTs, and two Counties supporting the proposed reference to 
the document, ``Maintaining Traffic Sign Retroreflectivity,'' and 
thereby only referencing the minimum retroreflectivity levels, rather 
than including them in the MUTCD text. Additionally, the Wisconsin DOT 
commented that referencing this document in GUIDANCE is too stringent, 
and requested that this reference be removed from the GUIDANCE. On the 
other hand, the FHWA received ten comments representing the ATSSA, the 
AHAS, the AHUA, Vermont Agency of Transportation, a representative of 
the sign industry, private citizens, and a consultant suggesting that 
the minimum maintained retroreflectivity levels should be included in 
the body of the MUTCD text in order to strengthen the proposed 
amendment as well as to make it easier for jurisdictions to find and 
adhere to the appropriate levels.
    The FHWA has considered these comments and has decided to propose 
to include the table of minimum retroreflectivity levels in Section 
2A.09 of the MUTCD as a new Table 2A-3. The FHWA agrees with these ten 
comments that a clear indication of the levels should be directly 
included in the MUTCD language as a convenience to all readers of the 
MUTCD. Moreover, the relationship between the FHWA's safety mission and 
the purpose of traffic control devices as described in the MUTCD, as 
well as the need to clearly satisfy the Congressional directive in the 
1993 Appropriations Act, led to the FHWA's decision to propose to 
include a reference to the table of minimum retroreflectivity levels in 
a GUIDANCE statement in the MUTCD. The FHWA

[[Page 26714]]

believes that this proposed change, in addition to the proposed methods 
listed in the MUTCD, provides sufficient flexibility for agencies or 
officials to determine methods that can be customized to fit their 
particular circumstances.
    The NACE, Saline County (Kansas), and Pierce County (Washington) 
suggested that the title of the minimum retroreflectivity table be 
changed from ``Minimum Maintained Retroreflectivity Levels'' to 
``Research Recommendations for Updated Minimum Retroreflectivity 
Levels.'' The FHWA disagrees because the table was developed based on 
the results of extensive research and the details describing this 
research have been provided in the document, ``Maintaining Traffic Sign 
Retroreflectivity.'' Therefore, the FHWA believes that there is no need 
to include ``Research Recommendations'' in the title.
    (3) Further clarification of the compliance period should be 
provided.
    In the NPA, the FHWA proposed to add target compliance dates for 
Section 2A.09 Minimum Retroreflectivity to the STANDARD statement in 
the Introduction to the MUTCD. The FHWA proposed a phase-in target 
compliance period of 7 years for regulatory, warning, and post-mounted 
guide signs and 10 years for overhead guide signs and street name signs 
from the effective date of the final rule for Revision No. 2 of the 
2003 MUTCD to minimize any impact on State or local governments.
    The NACE, Michigan and New Jersey DOTs, Saline County (Kansas), and 
Pierce County (Washington) all commented that the compliance periods 
needed to be clarified, since it was unclear as to whether agencies 
were to have an assessment or management process in place by the end of 
the compliance period, or if the intent was that the signs themselves 
be in compliance by the end of the compliance period.
    Therefore, in this SNPA, the FHWA proposes new language in the 
Introduction of the MUTCD that is intended to clarify the meaning of 
the compliance periods. Public agencies or officials having 
jurisdiction will have 2 years to identify and begin using a method to 
maintain sign retroreflectivity at or above the established minimum 
levels. In addition, the new language in this SNPA makes it clear that 
the 7- and 10-year compliance dates apply only to signs that have been 
identified using an assessment or management method as failing to meet 
the minimum retroreflectivity levels. The 7-year proposed compliance 
date for regulatory, warning, and ground-mounted guide signs (except 
for street name signs) was established to allow new signs with ASTM 
Type I materials \9\ just being installed to remain in place for their 
normal expected life \10\ before being removed and replaced with more 
efficient retroreflective sheeting materials. Similarly, the FHWA 
proposes the 10-year compliance date for street name signs and overhead 
guide signs because more durable materials are normally used on these 
signs.
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    \9\ ASTM Type designations are defined in ASTM D4956. From this 
point forward, the ASTM prefix will be omitted from the text, but 
should be implicitly assumed when a specific Type of material is 
designated.
    \10\ Wolshon, B., et al. Analysis and Predictive Modeling of 
Road Sign Retroreflectivity Performance. TRB Visibility Symposium, 
Iowa City, Iowa, June 2002. This paper can be found at https://
arrow.win.ecn.uiowa.edu/symposium/DraftPapers/VIS2002-17.pdf.
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    Because the proposed compliance dates are tied to the normal 
expected life of retroreflective materials, the FHWA believes that the 
changes proposed in this SNPA would lead to visibility improvements and 
safety enhancements without causing undue financial hardships. For 
those agencies and officials with jurisdiction already using sign 
maintenance practices that include retroreflectivity considerations, 
the proposed changes would have a negligible impact. For those agencies 
that do not already have a sign maintenance practice in place, the 
analysis described in the section ``Imposing additional time and 
resource burdens on public agencies'' and another analysis described 
near the end of this document demonstrate that the economic impacts 
would cause minimal additional expenses. Furthermore, the FHWA 
anticipates that the visibility improvements that are expected from 
these proposed changes would be derived from the physical removal and 
replacement of signs that have inadequate retroreflectivity rather than 
from an overall upgrade of all signs regardless of their 
retroreflective sheeting material condition.
    The following example is provided to clarify how the proposed 
compliance dates are tied to normal expected sign life. Assuming that 
these proposed changes become final on January 1, 2007, then agencies 
and officials with jurisdiction will have until January 1, 2009, to 
establish a sign assessment or management method and have it 
operational. Thus by January 1, 2009, agencies and officials will be 
identifying signs that need to be replaced because of assessed or 
anticipated insufficient retroreflectivity levels. Agencies and 
officials will then have until January 1, 2014, to bring the identified 
regulatory, warning, and ground-mounted guide signs, excluding street 
name signs, into conformance with the proposed table of minimum 
retroreflectivity levels. If an agency or officials are using Type I 
material for certain signs such as warning signs, they would have until 
January 1, 2014, to have those signs removed and replaced with signs 
with at least Type III material. Similarly, agencies and officials 
would have until January 1, 2017, to bring the identified street name 
signs and overhead guide signs into conformance with the proposed table 
of minimum retroreflectivity levels.
    The FHWA received comments from the American Public Works 
Association (APWA), the American Road and Transportation Builders 
Association (ARTBA), and a private citizen in support of the compliance 
periods proposed in the NPA. Seven comments representing the ATSSA, the 
AARP, two representatives of the sign industry, and two private 
citizens all opposed the proposed compliance periods. These comments 
stated that the periods were too long and should be shortened in order 
to improve the effectiveness of signs and therefore roadway safety more 
quickly. Several of the comments cited publications about roadway 
safety and the economic benefits to society of saving lives. The FHWA 
considered these comments, but believes that shortening the compliance 
period might place a financial hardship on State DOTs and local 
governments. In addition, the proposed MUTCD language described herein 
is intended to enhance safety above the current level. It is expected 
that safety will be enhanced during the transition periods associated 
with the compliance dates and these transition periods achieve a 
reasonable balance between the costs associated with the proposed 
changes and safety.
    Ten comments representing the NACE, Alabama, Arizona, Pennsylvania, 
Vermont, and Washington State DOTs, as well as McLean County 
(Illinois), Saline County (Kansas), Pierce County (Washington), and the 
City of Fort Worth (Texas) all opposed the compliance periods, stating 
that the compliance periods were too short. Many of these agencies 
cited economic concerns, while others suggested that the life cycle of 
the sign sheeting that they use is longer than the 7- and 10-year 
compliance periods, therefore the compliance period should be tailored 
more to the specific sign sheeting types used by agencies. Pierce 
County (Washington) suggested that the compliance period should be 15 
years,

[[Page 26715]]

which was the compliance period for minimum letter size on street name 
signs for streets and highways having a speed limit greater than 25 
mph.
    The FHWA disagrees with extending the compliance period because the 
FHWA believes the proposed target compliance period of 7 years would 
allow State and local agencies to replace their signs made with Type I 
materials within a normal replacement period of a commonly accepted 7-
year service life. In addition, the proposed 10-year compliance period 
for street name signs and overhead guide signs would allow an extended 
period of time because of the longer service life typically associated 
with those signs. Existing signs installed by those agencies that are 
already using higher-grade sign sheeting materials would likely meet 
the minimum retroreflectivity levels in the 7- and 10-year compliance 
periods, and would not need to be replaced. The proposed compliance 
periods also exceed the 6-year compliance period requested by the 
AASHTO Task Force on Retroreflectivity.
    (4) The visibility impacts associated with maintained sign 
retroreflectivity should be described.
    Respondents such as the County Engineers Association of Illinois--
District 3 stated that the concept of improved visibility as described 
in the proposed NPA was unclear. In addition, the AHAS pointed out that 
the concept of enhanced nighttime visibility has not been thoroughly 
verified. The following discussion demonstrates the FHWA's view 
regarding the impacts of this SNPA in terms of enhanced nighttime sign 
visibility. Besides establishing minimum retroreflectivity levels for 
certain sign types, the table of minimum retroreflectivity levels 
proposed for inclusion in the MUTCD also eliminates the use of certain 
types of retroreflective sheeting materials depending on the type of 
sign. For instance, in this SNPA (and in the previous NPA), the FHWA 
proposes that Type I material would be unacceptable for warning signs 
and for legends on ground-mounted guide signs, and Type I, II, and III 
materials would be unacceptable for legends on overhead guide signs. 
Research has shown that these restrictions are needed to accommodate 
the needs of older drivers who generally have diminished visibility 
capabilities when compared to their younger 
counterparts.11 12
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    \11\ Carlson, P.J. and H.G. Hawkins. Updated Minimum 
Retroreflectivity Levels for Traffic Signs. FHWA-RD-03-081. U.S. 
Department of Transportation, Federal Highway Administration, 
Washington, DC, 2003.
    \12\ Carlson, P.J., H.G. Hawkins, G.F. Schertz, D.J. Mace, and 
K.S. Opiela. Developing Updated Minimum In-Service Retroreflectivity 
Levels for Traffic Signs. In Transportation Research Record 1824, 
TRB, National Research Council, Washington, DC, 2003, pp. 133-143.
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    Although the impact of restricting some types of sign material for 
certain classes of signs cannot be precisely estimated, the enhanced 
sign performance or improved visibility can be estimated in various 
ways. For instance, a convenient way to compare the relative 
performance of warning signs is to compare the retroreflectivity levels 
of different sheeting materials. The typical retroreflection level for 
new yellow Type I materials is approximately 65 cd/lx/m2 and 
the typical retroreflection level for new yellow Type III beaded 
materials is approximately 230 cd/lx/m2. Based on these 
typical retroreflectivity levels, Type III warning sign material will 
have about 3.5 times more retroreflectivity than Type I warning sign 
material. However, the retroreflectivity levels used for this example 
are associated with a retroreflective geometry that is based on an 
observation angle of 0.2 degrees and an entrance angle of 4 degrees. 
Thus the increase in retroreflection of 3.5 times is associated with 
specific angles that will not be constant throughout a vehicle's 
approach to a sign.
    Another way to compare the relative performance of sheetingis to 
compare the fractional retroreflection, or RT.\13\ The 
fractional retroreflection is usually expressed as a percentage and can 
be thought of as a measure of the sign sheeting efficiency in terms of 
its ability to return light to the source in a cone-shaped pattern. By 
summing the retroreflectivity levels throughout a range of observation 
angles, the fractional retroreflection is perhaps a more useful measure 
to describe the performance of a sign throughout the range of distances 
and angles during which the information from the sign should be 
available to approaching motorists.
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    \13\ The fundamentals of retroreflection, including observation 
angle, entrance angle, and fractional retroreflection, are described 
in the International Commission on Illumination's report, 
``Retroreflection: Definition and Measurement'' CIE Publication 
54.2-2001, CIE Central Bureau, Vienna, Austria. The document is 
available at the following Web address: https:// www.cie.co.at/ 
framepublications. html.
---------------------------------------------------------------------------

    The fractional retroreflection of Type I material is about 8 
percent. For Type III beaded material, the fractional retroreflection 
is about 16 percent. For the microprismatic sign sheeting materials 
described in ASTM D4956-04, the fractional retroreflection is about 30 
to 35 percent. Based on these measures, the efficiency of warning signs 
in terms of their ability to return light to the source could be 
doubled by changing the sign sheeting from a Type I material to a Type 
III material and then could be doubled again by using one of the 
microprismatic materials currently defined in ASTM D4956-04. The FHWA 
believes that restricting some types of sign material for certain 
classes of signs will improve nighttime sign visibility to a level 
needed to accommodate older drivers.
    (5) The requirements in the proposal would impose additional time 
and resource burdens on public agencies.
    The Virginia DOT and Branch County (Michigan) both opposed the sign 
retroreflectivity language asserting that they would incur significant 
additional costs to meet the requirements. Furthermore, Virginia DOT 
and Branch County indicated that they have not received complaints 
about their signs, and that their older signs are replaced on a 
continuous basis.
    A potential outcome of the proposed MUTCD changes described herein, 
besides the improved nighttime traffic sign visibility as previously 
explained, is that sign life-cycle costs may be enhanced by using more 
durable retroreflective sheeting materials (as indicated by the case 
studies described above). For instance, Type I material typically has 
an in-service life of about 7 years, while Type III material usually 
has an in-service life of 10 years.\14\ Patents protecting the 
technology of Type III materials have expired, which has created a very 
competitive market. The cost difference between Type I and Type III 
materials is small. In addition, some agencies such as Indiana DOT \15\ 
have studied the in-service life of Type III materials and found that 
they can be expected to perform adequately for at least 12 years 
(factors such as geographic regions within the U.S. can impact the 
expected in-service life of traffic signs). Therefore, even though the 
initial costs of Type III materials are slightly higher than Type I 
materials, the longer material life can produce more economical 
lifecycle costs. The longer material life also results in sign 
technicians spending less time working within the right-of-way to 
replace deficient signs, thus reducing their exposure to being struck 
by out-of-control vehicles.
---------------------------------------------------------------------------

    \14\ Hawkins, G.H., P.J. Carlson, B. McCaleb, and C. McIlroy. 
Impact of Minimum Retroreflectivity Values on Sign Replacement 
Practices. FHWA/TX-97/1275-1F. College Station, TX, October 1996.
    \15\ Nuber L. and D. Bullock. Comparison of Observed 
Retroreflectivity Values with Proposed FHWA Minimums. Proceedings 
from the TRB's 81st Annual Meeting, Washington, DC, January 2002.

---------------------------------------------------------------------------

[[Page 26716]]

    It is important to note that the costs associated with the changes 
proposed in this SNPA should be based on the incremental cost of using 
a more efficient type of retroreflective material for the sign face 
when the sign is replaced prior to the compliance dates. It is also 
important to note that these costs should be only associated with the 
classes of signs that have restrictions on the types of sign sheeting 
materials that can be used. Currently, the MUTCD contains a GUIDANCE 
statement for nighttime sign inspections to maintain adequate sign 
retroreflectivity. Therefore, an agency's budget should already include 
the cost of replacing signs with deficient retroreflectivity.
    Agencies currently using the sheeting materials that will become 
restricted as proposed in this SNPA would have to absorb the costs of 
using more efficient sign sheeting material within the appropriate 
compliance dates. To estimate the number of signs made with Type I 
materials that would need to be upgraded as a result of the proposed 
changes in this SPNA, data from a previous FHWA-sponsored report \16\ 
were used since no other national data are currently available. The 
report describes sign information data that were collected from 16 
States and 9 local agencies, representing a reasonable national 
coverage. While the specific dates of the sign information are not 
referenced in the report, based on the publication date of the report, 
and assuming the data had been collected a few years before the report 
was published, it is reasonable to assume the data are now 
approximately 10 years old. This is important because many agencies 
might have already upgraded their sign sheeting policy to something 
other than Type I and therefore the following estimates might be 
conservative and might represent the worse case scenario.
---------------------------------------------------------------------------

    \16\ McGee, H.W. and S. Taori. Impacts on State and Local 
Agencies for Maintaining Traffic Signs Within Minimum 
Retroreflectivity Guidelines. FHWA-RD-97-053, FHWA, Washington, DC, 
1998.
---------------------------------------------------------------------------

    The State agency data included a total of 2,757 yellow and orange 
warning signs. The dates of installation of these signs ranged from 
1973 to 1995 with an average installation date of 1989. Of that sample, 
1,443 (or 52.3 percent) were made with Type I materials.
    The local agency data included a total of 2,030 yellow and orange 
warning signs. The dates of installation of these signs ranged from 
1979 to 1994 with an average installation date of 1990. Of that sample, 
1,294 (or 63.7 percent) were made with Type I materials.
    The FHWA proposes to eliminate Type I material for ground-mounted 
guide sign legends. Using the same data set described above, it is 
possible to estimate the number of ground-mounted guide signs using 
legends made with Type I materials. For the State agencies, a total of 
929 signs were measured and 420 (45.2 percent) of the legends were made 
with Type I material. For the local agencies, a total of 300 signs were 
measured and 111 (37.0 percent) of the legends were made with Type I 
material.
    Finally, the FHWA proposes to eliminate Type I, II, and III 
materials for overhead guide sign legends. The previously referenced 
data source contains no overhead signing data. Therefore, the impacts 
of the overhead guide sign policy as proposed in this SNPA were 
assessed using the results of a Virginia DOT survey completed in early 
2005.\17\ That survey included questions for State agencies regarding 
overhead guide signs and retroreflective sheeting. Of the 21 States who 
responded, one State (4.8 percent) uses Type I for legend material, 
eight States (38.1 percent) use Type III for legend material, and the 
remaining 12 States (57.1 percent) use Type VII, VIII, or IX for legend 
material.
---------------------------------------------------------------------------

    \17\ From an unpublished Virginia DOT survey of State DOT 
overhead sign lighting and sheeting policies, a copy of which is 
available for inspection on the docket.
---------------------------------------------------------------------------

    Based on this analysis, it can be estimated that approximately 50 
to 60 percent of the in-service yellow and orange warning signs use a 
Type I material for their sign face. Similarly, it can be estimated 
that approximately 50 to 60 percent of the in-service ground-mounted 
guide signs use a Type I material for the legend, and that 
approximately 40 percent of the States use a Type I, II, or III 
material for the legend of their overhead guide signs. The proposed 
table of minimum retroreflectivity levels would require that these 
signs be replaced with more efficient retroreflective materials before 
the respective compliance dates (7 years for ground-mounted signs and 
10 years for street name signs and overhead guide signs).

Discussion of Other Comments

    In addition to the five major issues discussed in the previous 
section, the FHWA also received comments that can be grouped into the 
following topics:
    (6) Extension of the initial NPA comment period;
    (7) Maintaining traffic sign retroreflectivity;
    (8) Methods to maintain traffic sign retroreflectivity;
    (9) Potential safety implications of maintained sign 
retroreflectivity;
    (10) Signs excluded from the proposed rule;
    (11) Levels of minimum retroreflectivity and contrast ratios;
    (12) Adding minimum retroreflectivity levels for larger observation 
angles;
    (13) Adding types of sheeting to the minimum retroreflectivity 
table;
    (14) Need for technical support and training;
    (15) Changes to Section 2A.22 Maintenance; and
    (16) Pavement markings.
    This section of this SNPA contains a discussion of each of these 
topics.
    (6) Extension of the initial NPA comment period.
    The NCUTCD, the AASHTO, and Connecticut DOT all requested that the 
comment period be extended so that their members would have a 
sufficient period of time to review and develop comments. As a result, 
the FHWA published a notice in the Federal Register on October 22, 
2004, that extended the comment period to February 1, 2005 (69 FR 
62007). The ATSSA opposed any extension of the comment period, while 
the AHUA opposed extending the comment period beyond February 1, 2005.
    (7) Maintaining traffic sign retroreflectivity.
    In Section 1A.11 Relation to Other Publications, the FHWA proposed 
in the NPA to add the 2003 version of the publication ``Maintaining 
Traffic Sign Retroreflectivity'' to the list of other publications that 
are useful sources. There were 32 comments from the AASHTO, the NACE, 
27 State DOTs, Saline County (Kansas), Pierce County (Washington), and 
a consultant in support of adding a reference to the publication 
``Maintaining Traffic Sign Retroreflectivity'' to the discussion of 
useful sources of information. The primary reason for their support was 
the fact that the table showing the minimum levels of 
retroreflectivity, which is contained in the referenced publication, 
would thereby not be explicitly included within the body of the MUTCD 
language. Instead, the table of minimum values would be a part of the 
referenced publication and could easily be updated as the science of 
sign visibility continued to evolve.
    While the FHWA still feels that the referenced document 
``Maintaining Traffic Sign Retroreflectivity'' is a useful document 
that provides additional details of the methods available to satisfy 
the intent of the MUTCD sign retroreflectivity language, the FHWA has 
decided to include the table of

[[Page 26717]]

minimum retroreflectivity levels in the MUTCD text as previously 
described. This SNPA references the 2005 Edition of the document 
entitled ``Maintaining Traffic Sign Retroreflectivity'' that has been 
updated to reflect the proposed changes described in this SNPA.
    The ATSSA and a consultant suggested that the MUTCD should include 
a statement mentioned in the ``Maintaining Traffic Sign 
Retroreflectivity'' document that states, ``It should be noted that 
there may be situations where, based on engineering judgment, an agency 
may want to provide greater retroreflectivity.'' The FHWA agrees with 
this concept, but because there has not been sufficient research to 
document the situations or to what extent additional retroreflectivity 
would be needed, it is premature to add such a statement. However, the 
FHWA notes that the proposed SNPA would not restrict agencies from 
using higher levels of retroreflectivity if, based on engineering 
judgment or studies, the agencies determine that higher levels are 
warranted.
    The NACE, Saline County (Kansas), and Pierce County (Washington) 
suggested amending the ``Maintaining Traffic Sign Retroreflectivity'' 
document to provide the proper context for use of the table showing the 
retroreflectivity values. In addition, the NACE, Saline County 
(Kansas), and Pierce County (Washington) suggested that the FHWA 
provide additional information on how a practitioner would use the 
table of values to set up a management or assessment program. The FHWA 
agrees, and has updated the ``Maintaining Traffic Sign 
Retroreflectivity'' document to provide additional information to 
support the minimum retroreflectivity table, which the FHWA now 
proposes to include in the MUTCD. In addition, the FHWA has provided 
and will continue to provide training material to help agencies comply 
with the proposed rule.
    (8) Methods to maintain traffic sign retroreflectivity.
    The NPA included five methods that agencies can use to maintain 
traffic sign retroreflectivity at or above the established minimum 
levels. The FHWA received 26 comments from the AASHTO, the NACE, the 
ARTBA, 18 State DOTs, and two counties supporting the flexibility that 
these methods provide. Other respondents provided a mixed set of 
requests asking for additional details in some cases and for less 
detail in other cases. The FHWA considered the extent of these comments 
and has retained the list of assessment and management methods in 
Section 2A.09, but has provided less detail about each specific 
assessment and management method. The additional details requested will 
be provided in the referenced document entitled, ``Maintaining Traffic 
Sign Retroreflectivity (2005 Edition).''
    (9) Potential safety implications of maintained sign 
retroreflectivity.
    Forty-six comments representing State and local DOTs, the AASHTO, 
the NACE, the AARP, the ARTBA, industry, consultants, and private 
citizens agreed with the general principle that it is desirable to 
maintain adequate levels of sign retroreflectivity to enhance safety 
for motorists during the hours of darkness and during adverse weather. 
However, the AHAS questioned the sustainability of the NPA proposal in 
terms of safety validation.
    Although there has not been a study definitively linking the safety 
benefits of maintaining or upgrading retroreflective sign sheeting 
materials, there have been some investigations that demonstrate 
potential safety benefits of upgrading sign sheeting materials.\18\ The 
FHWA believes these investigations provide support for the potential 
safety benefits of upgrading these materials.
---------------------------------------------------------------------------

    \18\ D. Ripley. Quantifying the Safety Benefits of Traffic 
Control Devices--Benefit-Cost Analysis of Traffic Sign Upgrades. 
Accepted for publication in the proceedings of the 2005 Mid-
Continent Transportation Research Symposium, Ames, Iowa, August 
2005. This paper can be found at https://tcd.tamu.edu/Documents/
MinRetro/MinRetro.htm.
---------------------------------------------------------------------------

    The City of Sioux City, Iowa has a population of approximately 
85,000. The City was using Type I materials prior to 1995 when a sign 
upgrade program was initiated that started with Type III material, but 
eventually moved to a Type IX material. The City was replacing 
approximately 10 percent of its total sign inventory per year. Using 
crash data, the City determined that the crashes per million vehicle 
miles dropped from about 6.5 in 1995 to about 4.0 in 1999. In addition, 
the ratio of nighttime to daytime crashes during the same period 
dropped from about 1.19 to about 0.96. The City estimated the costs of 
the program to be approximately $150,000 for the three years from 1997 
to 1999. During that same time, the City estimated a total cost savings 
of almost five million dollars, using an average crash cost of $2,350. 
The benefit-cost ratio was estimated to be 34:1.
    Putnam County, New York is a rural county located just north of New 
York City. The County is responsible for maintaining over 115 miles of 
roads. In 1992, all county road signs were fabricated with Type I 
materials. In 1993 and 1994, the County upgraded over 2,000 traffic 
signs to Type III material (for regulatory and warning signs on 
roadways with recommended speeds of 30 mph and above) and Type IX 
material (for arrows and chevrons as well as signs on roadways with 
recommended speeds of 25 mph and below). Three county roads were chosen 
for analysis to determine the impacts of the sign sheeting upgrade 
program. Two of the roads were chosen because they had the highest 
traffic volumes in the county and the third road was chosen because it 
had the highest crash rate in the county. The available accident 
statistics for 1992 (the year before the sign upgrades) and 1995 (the 
year after the higher performance signs were installed) were analyzed 
in this study. Based on the results of this study, the difference in 
reported crashes between 1992 and 1995 was impressive. The total number 
of crashes was reduced by 26 percent, the number of injury crashes was 
reduced by 23 percent, and the number of nighttime crashes was reduced 
by 50 percent.
    There are a number of limitations associated with each of these 
investigations. For example, other roadway improvements such as fresh 
pavement overlays and new pavement markings were implemented 
simultaneously with the signing upgrades, which make the determination 
of the safety effects directly associated with the signing upgrades 
difficult to assess. In addition, the investigations have not been 
individually published in peer-reviewed journals.
    Despite these limitations, these investigations demonstrate that 
upgrading sign sheeting material can lead to improved safety. More 
importantly, maintaining adequate sign retroreflectivity is consistent 
with one of the FHWA's primary goals, which is to improve safety on the 
nation's streets and highways. Many safety strategies are dependent on 
adequate sign visibility. The FHWA expects that improvements to 
nighttime visibility of traffic signs will help drivers better navigate 
the roads at night and thus promote safety and mobility, which is 
consistent with the purposes of traffic control devices as described in 
Section 1A.01--Purposes of Traffic Control Devices of the MUTCD. 
Improvements in sign visibility will also support the FHWA's efforts to 
be responsive to the needs of older drivers, which is important because 
the number of older drivers is expected to increase significantly 
during the next 30 years.
    (10) Signs excluded from the proposed rule.
    In the NPA, the FHWA proposed to list in an OPTION paragraph signs 
that agencies may exclude from the

[[Page 26718]]

proposed assessment methods and minimum maintained sign 
retroreflectivity levels. The signs that the FHWA proposed to exclude 
were: (1) Parking, Standing, and Stopping signs (R7 and R8 series), (2) 
Walking, Hitchhiking, and Crossing signs (R9 series, R10-1 through R10-
4b), (3) Adopt-A-Highway series, (4) All signs with blue or brown 
backgrounds, and (5) Bikeway signs that are intended for exclusive use 
by bicyclists and/or pedestrians. The intent was that the proposed list 
would not exclude those signs from the existing retroreflectivity and 
maintenance requirements and GUIDANCE that are currently included in 
the MUTCD.
    The FHWA received 10 comments from Michigan DOT, Monroe County (New 
York), the ATSSA, the AARP, industry, and consultants in response to 
the proposed language in the OPTION paragraph described above. The FHWA 
considered the comments and has decided not to make any changes. While 
one of the key goals of the proposed MUTCD language described herein is 
to promote safety, the FHWA believes that the minimum retroreflectivity 
levels proposed in this SNPA should include, at a minimum, the most 
important signs--regulatory, warning, and guide signs.
    The FHWA also received comments from the AHAS, the ATSSA, industry, 
and two consultants indicating that blue and brown signs should be 
included in the table of minimum retroreflectivity levels. Research is 
underway to provide a set of recommended minimum retroreflectivity 
levels for signs with blue and brown backgrounds, but there are no 
immediate plans to establish minimum retroreflectivity levels for these 
or other sign colors. The FHWA seeks comments on the need for 
retroreflectivity levels to be developed for signs with blue and brown 
backgrounds.
    (11) Levels of minimum retroreflectivity and contrast ratios.
    A representative of the sign industry opposed the levels of 
retroreflectivity proposed in the NPA, stating that they corresponded 
to a level of sign performance that is too low, and do not meet the 
needs of drivers on roads with both horizontal and vertical curvature, 
drivers on roads that are located in high ambient light conditions, 
drivers of large trucks, or older drivers.
    The FHWA acknowledges that the initial research did not cover all 
conditions possible; however, providing adequate traffic sign luminance 
for all drivers in the worst possible situations could not be 
accomplished by retroreflectivity alone and would require additional 
illumination. The initial research did include sensitivity analyses for 
different vehicle sizes, including large trucks. Also, the subjects 
used in the studies were at least 55 years of age with a median age of 
62 years (the oldest driver to complete the study was over 80 years of 
age). The minimum retroreflectivity levels have been estimated to 
provide a nighttime accommodation level that corresponds to levels 
above 90 percent of the nighttime driving population. It should be 
noted that more studies are needed as recommended in some FHWA 
publications.19 20
---------------------------------------------------------------------------

    \19\ Carlson, P.J. and H.G. Hawkins. Updated Minimum 
Retroreflectivity Levels for Traffic Signs. Final Report FHWA-RD-03-
081. Federal Highway Administration, Washington, DC, 2003.
    \20\ Carlson, P.J., H.G. Hawkins, G.F. Schertz, D.J. Mace, and 
K.S. Opiela. Developing Updated Minimum In-Service Retroreflectivity 
Levels for Traffic Signs. In Transportation Research Record 1824, 
TRB, National Research Council, Washington, DC, 2003, pp. 133-143.
---------------------------------------------------------------------------

    The Virginia DOT questioned whether minimum contrast ratios are 
needed for the white on green signs since a minimum contrast ratio is 
shown for white on red signs. The FHWA believes that contrast ratios 
are not needed for white on green signs since green signs are made with 
green sheeting and are much more durable in terms of maintaining their 
color than red signs, which are made from silk screening and thus fade 
towards white as the silk screen's red color fades.
    A consultant opposed the contrast ratios, stating that contrast 
ratios of 3:1 are too low, and recommended that the ratio be raised to 
4:1. The FHWA disagrees because the key issue is that the contrast 
ratio for the minimum retroreflectivity levels is assigned to red 
signs. These are signs that have unique shapes and/or sizes in addition 
to their legends. Therefore, the information they convey is provided 
through an iconic manner, rather than textual. For iconic signs, or 
recognition-based tasks, a contrast ratio of 3:1 is adequate.\21\ For 
legibility-based tasks, contrast ratios higher than 3:1 would be 
preferred.
---------------------------------------------------------------------------

    \21\ Carlson, P.J. and H.G. Hawkins. Updated Minimum 
Retroreflectivity Levels for Traffic Signs. Final Report FHWA-RD-03-
081. Federal Highway Administration, Washington, DC, 2003.
---------------------------------------------------------------------------

    The Arizona DOT opposed any reference in the MUTCD to actual 
minimum retroreflectivity values, either in research or in another FHWA 
publication. The Arizona DOT states that the research values have 
fluctuated in the past 10 years, and with so many other variables 
affecting the performance of the signs at night, including vehicle 
headlights, driver eyesight, weather conditions, etc., the Arizona DOT 
does not agree with the values as set by the ASTM sheeting types. The 
FHWA disagrees. The FHWA decided to use the ASTM sheeting type 
designations for two reasons. First, there is not a better or as well 
recognized classification scheme for retroreflective sheeting, and 
second, luminance would be a better measure of sign performance, but 
there is not a practical way to consistently measure luminance in the 
field. As new ASTM sheeting types are designated, the minimum 
retroreflectivity table will be updated as appropriate.
    The New Jersey DOT suggested that consideration be given to the 
fact that retroreflectivity of signs can be taken to a level where the 
glare is unsatisfactory, and that some signs with a gloss finish 
reflect light from headlights to a point where the sign becomes 
illegible. The FHWA is not aware of any research or data showing that 
retroreflective signs are too bright, and believes that the minimum 
levels will not lead to signs being excessively retroreflective.
    (12) Adding minimum retroreflectivity levels for larger observation 
angles.
    Two comments from the sign industry and another from a consultant 
opposed the 0.2-degree observation angle used in the referenced table 
of minimum retroreflectivity levels, and suggested that a 0.5-degree 
observation angle be included in order for the levels to be more 
meaningful and more easily adaptable in the future. The FHWA agrees 
that changing the standard observation angle to 0.5 degrees would 
provide a more meaningful retroreflectivity value. Research has been 
completed that supports moving toward the 0.5-degree concept and the 
ASTM has started working toward a revision to its specifications to 
describe 0.5-degree measurements.\22\ However, there are currently no 
hand-held devices that measure an observation angle of 0.5 degrees 
conveniently when conducting field measurements. While there are some 
devices currently in the design and prototype stage, the FHWA does not 
believe it is practical to implement minimum retroreflectivity levels 
based on an observation angle of 0.5 degrees until measuring devices 
become readily available. At that time there may be a need for an 
alternative table and a transition period established while the 0.2-
degree measurement geometries and devices are phased out.
---------------------------------------------------------------------------

    \22\ Changes to ASTM E1709 are currently underway to include the 
possibility of measuring sign retroreflective sheeting at 
alternative observation angles, including 0.5 degrees.
---------------------------------------------------------------------------

    (13) Adding types of sheeting to the minimum retroreflectivity 
table.

[[Page 26719]]

    The ATSSA, Texas DOT, a representative of the sign industry, and a 
private citizen all commented that the Minimum Maintained 
Retroreflectivity Levels table did not include values for Type IV 
material, which is now used by many State and local DOTs. During the 
development of the FHWA minimum retroreflectivity levels, the Type IV 
designation was a leftover designation for a material that was 
discontinued. Types VII, VIII, and IX materials were introduced and 
this left a large gap in performance between the Type III materials and 
the Type VII, VIII, and IX materials. This gap was recently filled when 
manufacturers began offering a product with retroreflectivity levels 
near the previous Type IV designation. The ASTM subsequently revamped 
the Type IV retroreflectivity levels as a result of the increased 
interest in Type IV materials. Based on the current commercial 
availability of Type IV retroreflective material, the FHWA proposes in 
this SNPA to include requirements for Type IV material in the table of 
Minimum Maintained Retroreflectivity Levels.
    The ATSSA, a consultant, and a private citizen all commented that 
the Minimum Maintained Retroreflectivity Levels table did not include 
values for Type VI, which is in wid