Uniform Criteria for State Observational Surveys of Seat Belt Use, 18042-18059 [2011-7632]

Agencies

• National Highway Traffic Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 76, Number 63 (Friday, April 1, 2011)]
[Rules and Regulations]
[Pages 18042-18059]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-7632]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

23 CFR Part 1340

[Docket No. NHTSA-2010-0002]
RIN 2127-AK41


Uniform Criteria for State Observational Surveys of Seat Belt Use

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation (DOT).

ACTION: Final rule.

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

SUMMARY: This Final Rule amends the regulation establishing uniform 
criteria for designing and conducting State seat belt use observational 
surveys and the procedures for obtaining NHTSA approval of survey 
designs, and provides a new form for reporting seat belt use rates to 
NHTSA. Since the adoption of the Uniform Criteria in 1998, NHTSA and 
the States have accumulated substantial experience in the design and 
implementation of seat belt use surveys. This experience has provided 
insight into factors that could affect survey accuracy and reliability. 
In addition, technological improvements in road inventories have made 
it possible to select observation sites that are more representative of 
the road segments in the State in a more cost effective manner. For 
these reasons, NHTSA is revising the Uniform Criteria so that future 
surveys will give States more accurate data to guide their occupant 
protection programs.

DATES: This Final Rule becomes effective on May 2, 2011.

FOR FURTHER INFORMATION CONTACT: For program issues: Mr. Jack Oates, 
Chief, Program Implementation, Regional Operations and Program 
Delivery, National Highway Traffic Safety Administration, 1200 New 
Jersey Avenue, SE., NTI-200, Washington, DC 20590. Telephone number: 
202-366-2730; E-mail: Jack.Oates@dot.gov.
    For statistical issues: Dr. Chou-Lin Chen, Chief, Mathematical 
Analysis Division, National Center for Statistics and Analysis, 
National Highway Traffic Safety Administration, 1200 New Jersey Avenue, 
SE., NVS-421, Washington, DC 20590. Telephone number: 202-366-1048; E-
mail: Chou-Lin.Chen@dot.gov.
    For legal issues: Ms. Jin Kim, Attorney-Advisor, Office of the 
Chief Counsel, National Highway Traffic Safety Administration, 1200 New 
Jersey Avenue, SE., NCC-113, Washington, DC 20590. Telephone number: 
202-366-1834; E-mail: Jin.Kim@dot.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Notice of Proposed Rulemaking
III. Comments
    A. In General
    B. General Cost
    C. Definitions
    D. Selection of Observation Sites
    E. Assignment of Observation Times
    F. Observation Procedures
    G. Quality Control
    H. Computation of Estimates
    I. Submission and Approval of Seat Belt Survey Design
    J. Re-Selection of Observation Sites
    K. Annual Reporting Requirements
IV. Statutory Basis for This Action
V. Regulatory Analyses and Notices
    A. Executive Order 12866 and Regulatory Policies and Procedures
    B. Regulatory Flexibility Act
    C. Executive Order 13132 (Federalism)
    D. Executive Order 12988 (Civil Justice Reform)
    E. Paperwork Reduction Act
    F. Unfunded Mandates Reform Act
    G. National Environmental Policy Act
    H. Executive Order 13175 (Consultation and Coordination With 
Indian Tribes)
    I. Regulatory Identifier Number (RIN)
    J. Privacy Act
    K. Congressional Review of Agency Rulemaking

I. Background

    Section 1403 of the Transportation Equity Act for the 21st Century 
(TEA-21) (Pub. L. 105-178) authorized a seat belt incentive grant 
program that awarded grant funds to States based on a State's seat belt 
use rate. On September 1, 1998, the National Highway Traffic Safety 
Administration (NHTSA) published as an interim final rule the criteria 
to ensure accurate and representative measurements of a State's seat 
belt use rate, known as the Uniform Criteria for State Observational 
Surveys of Seat Belt Use (the Uniform Criteria). See 63 FR 46389. On 
March 14, 2000, NHTSA published a Final Rule, adopting the Uniform 
Criteria with one clarifying change.\1\ See 65 FR 13679.
---------------------------------------------------------------------------

    \1\ In 2000, NHTSA clarified that States are permitted to 
``cluster sample,'' i.e., group observation sites according to 
geographic areas to minimize travel time and distance required to 
conduct the observations.
---------------------------------------------------------------------------

    The Safe, Accountable, Flexible, Efficient Transportation Equity 
Act: A Legacy for Users (SAFETEA-LU) (Pub. L. 109-59), enacted on 
August 10, 2005, did not reauthorize the seat belt incentive grant 
program. However, SAFETEA-LU established new administrative 
requirements relating to a State's qualification for a highway safety 
grant under 23 U.S.C. 402. One such requirement is that the State must 
provide satisfactory assurances that it will conduct an annual 
Statewide seat belt use survey in accordance with the criteria for 
State seat belt use rate measurement established by the Secretary of 
Transportation.\2\ In August 2005, NHTSA notified the States and 
Territories that the Statewide surveys conducted in accordance with the 
Uniform Criteria for State Observational Surveys of Seat Belt Use, as 
published at 23 CFR part 1340, would satisfy the administrative 
requirements of Section 402. In addition, the implementing guidelines 
for the safety belt performance grant program under 23 U.S.C. 406 
provide that seat belt use surveys conducted in accordance with the 
Uniform Criteria serve as the basis for an award under the seat belt

[[Page 18043]]

performance provisions of that grant program.
---------------------------------------------------------------------------

    \2\ 49 CFR 1.50 (delegation of authority to Administrator of 
National Highway Traffic Safety Administration).
---------------------------------------------------------------------------

    Since the adoption of the Uniform Criteria in 1998, NHTSA and the 
States have accumulated substantial experience in the design and 
implementation of seat belt use surveys. This experience has provided 
insight into factors that could affect survey accuracy and reliability. 
In addition, technological improvements in road inventories have made 
it possible to select observation sites that are more representative of 
the road segments in the State in a more cost effective manner. For 
these reasons, NHTSA proposed to revise the Uniform Criteria so that 
future surveys would give States more accurate data to guide their 
occupant protection programs.

II. Notice of Proposed Rulemaking

    On January 28, 2010, NHTSA published a notice of proposed 
rulemaking (NPRM) to amend the Uniform Criteria. See 75 FR 4509. NHTSA 
proposed several key changes to the 1998 Uniform Criteria. In 
particular, the agency proposed to revise the geographic coverage of 
the sampling frame from the population-based exclusion criterion to a 
fatality-based exclusion criterion and to identify the road types that 
are required to be included in a State's sampling frame. The proposal 
also changed the precision requirement from a five percent relative 
error to a 2.5 percentage point standard error. In addition, the agency 
proposed quality control procedures, such as quality control monitors, 
training and statistical review, to help ensure accuracy and 
consistency across all State surveys. Finally, the agency proposed 
submission of additional information from the survey results as part of 
a State's annual certification, including the data source of the 
sampling frame, exclusions applied to the sampling frame, procedures 
for collecting additional data to reduce the nonresponse rates, 
explanation of any imputation methods, procedures to adjust the 
sampling weight, and procedures to be followed if the standard error is 
exceeded.

III. Comments

    By the close of the comment period on March 29, 2010, the agency 
received submissions from 27 commenters in response to the NPRM. 
Commenters included the following State agencies: California Office of 
Traffic Safety (CA OTS), Colorado Department of Transportation (CO 
DOT), Idaho Transportation Department (ID DOT), Illinois Department of 
Transportation (IL DOT), Iowa Governor's Traffic Safety Bureau--
Department of Public Safety (IA TSB), Kansas Department of 
Transportation (KS DOT), Louisiana Highway Safety Commission--
Department of Public Safety and Corrections (LA HSC), Maine Bureau of 
Highway Safety (ME DPSC), Missouri Highway Safety Division--Department 
of Transportation (MO DOT), Nevada Department of Public Safety 
(prepared by University of Nevada--Las Vegas) (NV DPS), New Hampshire 
Highway Safety Agency (NH HSA), New York Governor's Traffic Safety 
Committee--Department of Motor Vehicles (NY TSC), North Dakota 
Department of Transportation (ND DOT), Oregon Department of 
Transportation (OR DOT), Pennsylvania Department of Transportation (PA 
DOT), Texas Department of Transportation (TX DOT), Washington Traffic 
Safety Commission (WA TSC), West Virginia Governor's Highway Safety 
Program (WV HSP), Wisconsin Division of State Patrol, Bureau of 
Transportation Safety--Department of Transportation (WI State Patrol), 
Wyoming Highway Safety Program--Department of Transportation (WY HSP). 
Additional commenters included two associations--Governor's Highway 
Safety Association (GHSA) and International Association of Chiefs of 
Police (IACP); three professors and staff--Mississippi State University 
(MS State Univ.), New Jersey Institute of Technology (NJIT) and Old 
Dominion University (ODU); one consultant to a State--Peters and 
Associates Engineers Inc. (Peters & Assoc.); and one interested member 
of the public.

A. In General

    Several commenters expressed general support for revising the 
criteria. These commenters stated that the changes to the protocol are 
appropriate and timely and will enhance the accuracy and consistency of 
seat belt use surveys. (E.g., GHSA at 1; WI State Patrol at 1; WA TSC 
at 1; TX DOT at 1; CA OTS at 1. See also NV DPS at 9; ODU at 1.) In 
addition to expressing general support for revising the criteria, these 
commenters also had more specific comments regarding different aspects 
of the proposal. The agency addresses these comments below under the 
appropriate heading.
    Some commenters expressed general concern with revising the Uniform 
Criteria. One commenter suggested reducing the frequency of State 
observational surveys, and one commenter suggested expanding the 
National Occupant Protection Use Survey (NOPUS) to each State instead 
of requiring States to conduct independent surveys. (WI State Patrol at 
1; CO DOT at 1.) We decline to adopt these commenters' suggestions as 
Section 402 requires each State to provide assurances that it will 
conduct annual Statewide seat belt use surveys in accordance with the 
Uniform Criteria to ensure that the measurements are accurate and 
representative.
    One commenter believed that changing the survey criteria at the end 
of the authorization was not cost effective unless a seat belt 
incentive program formed a part of the future authorization. (LA HSC at 
1.) In the NPRM, we stated that the purpose of revising the criteria 
was to improve the accuracy and reliability of surveys conducted by 
States. We believe it is necessary to do so now based on our experience 
reviewing State survey results. Regardless of whether a seat belt 
incentive program is part of a future authorization, improved data will 
enable States to guide their highway safety program evaluation and 
program management more effectively now.
    The NH HSA stated that the most significant effect of the proposed 
change would be damage to trend information. (NH HSA 1.) The commenter 
further stated that policy analysis based on previous methodology would 
no longer be relevant as a tool to measure seat belt usage. Id. For 
some States, seat belt use rate estimates obtained from a survey 
meeting the new criteria may depart from the trend of survey outcomes 
in recent years. However, any departure from the trend will reflect the 
fact that the data will be more accurate and more reliable. 
Specifically, observation sites will be drawn from a more up-to-date 
and comprehensive road inventory. The seat belt survey will also be 
less biased toward urban areas due to the shift from a population-based 
exclusion to a fatality-based exclusion. (See discussion in Section 
III.D.1 below.) Finally, the survey will have greater precision due to 
the shift from a five percent relative error to a 2.5 percentage point 
standard error. (See discuss in Section III.D.5 below.) NHTSA believes 
that the need for more accurate and reliable data outweighs concerns 
about departure from trends reflected under the 1998 Uniform Criteria.
    The CO DOT stated that the proposal did not address the large gap 
in data through lack of nighttime observations. (CO DOT at 1.) As we 
stated in the NPRM, although nighttime observations of seat belt use 
may provide States with useful data, the agency believes that several 
factors weigh against extending the sampling requirements. First, 
extending the sampling requirement to nighttime observations would 
reduce

[[Page 18044]]

the value, for comparison purposes, of survey results from previous 
years' data. States and other interested parties use this information 
to determine the impact of various seat belt use programs and 
activities. In addition, seat belt use is difficult to reliably observe 
in the dark, even in the most well-lit areas. Nighttime observations 
are also less safe for data collectors than daytime observations 
because data collectors are less conspicuous and exposed to an 
increased presence of impaired drivers. For these reasons, the agency 
declines to change the rule in response to this comment.
    The LA HSC suggested that traffic cameras positioned in 
predetermined locations will provide higher data quality at a fraction 
of the costs of manual collection and will reduce exposure of data 
collectors to highway hazards. (LA HSC at 1.) The Uniform Criteria do 
not prohibit States from using traffic cameras to conduct seat belt use 
observations. However, States must still comply with the other 
provisions of the Uniform Criteria, such as observation procedures 
(Sec.  1340.7) and quality control (Sec.  1340.8). With this 
clarification, no change is made to the rule.
    The OR DOT suggested that States should be allowed to continue 
using their current survey methodology but adjust sampling to re-weight 
observation sites using the proposed fatality-based criterion. (OR DOT 
at 2.) Much of the survey methodology in the revised criteria is a 
clarification of the 1998 Uniform Criteria. The major change for most 
States will be in the sampling frame--changing from a population-based 
exclusion of counties to a fatality-based exclusion of counties and an 
updated road inventory. Because of this change, we expect that the 
large majority of States will have to re-select a probability sample of 
observation sites. However, some States already may be in close 
compliance with the revised criteria and may not need to make 
significant changes to their current survey design.
    NHTSA received four comments requesting additional guidance. The 
IACP and WV HSP requested greater guidance and technical assistance on 
conducting surveys, including common data collection procedures and 
approaches for calculation of sampling error estimates. (IACP at 1; WV 
HSP at 2.) The OR DOT and NV DPS requested a sample of an acceptable 
survey design for States. (OR DOT at 2; NV DPS at 7.) The agency 
intends to provide technical assistance, such as providing county-by-
county breakdowns of passenger motor vehicle occupant fatalities and an 
inventory of roads. In addition, NHTSA is developing a sample of an 
acceptable survey design to assist the States' redesign efforts. This 
sample design will provide general guidance for designing a seat belt 
use survey, including the calculation of survey standard error. 
However, the Final Rule still requires States to rely on their own 
statistician to design, conduct and analyze the data. As we discuss in 
Section III.G below, the purpose of requiring statistician involvement 
is to ensure that both the survey design and the annual reporting of 
seat belt use rates are carried out in a methodologically-sound manner. 
No change to the Final Rule is made in response to these comments.
    Two commenters mentioned a ``self-report survey'' and a ``public 
opinion survey'' as further increasing costs to the States. (IACP at 2; 
CO DOT at 1.) We believe the commenters are referring to the annual 
public opinion survey that States voluntarily agreed to conduct and 
report on as part of their core highway safety program performance 
measures. We note that the public opinion survey is not mandatory and 
not related to the seat belt survey criteria. Therefore, we do not 
address these comments here.
    The OR DOT stated that the revised criteria require new performance 
measures. (OR DOT at 2.) The revised criteria do not impose a 
performance measure--States are not required to meet a specific seat 
belt use rate. Rather States are required to conduct surveys that are 
consistent with the revised criteria so that seat belt use rate 
estimates are more accurate and reliable.
    The agency received more specific comments regarding different 
aspects of the proposal, including requests for clarification and 
recommendations to change the proposal. The agency addresses these 
comments below under the appropriate heading.

B. General Cost

    One interested member of the public stated that conducting such 
surveys is a waste of taxpayer's money. (Jean Public at 1.) As 
discussed in Section III.A. above, States are required by statute to 
provide assurances that it will conduct annual Statewide seat belt use 
surveys in accordance with the Uniform Criteria to ensure that the 
measurements are accurate and representative. See 23 U.S.C. 402.
    A number of commenters expressed general concerns regarding 
increased costs as a result of the revised Uniform Criteria, especially 
related to the number of observation sites, and the requirements for 
quality control monitoring and additional observations as a result of 
nonresponse rates. (WA TSC at 4; OR DOT at 2; IACP at 2; ID DOT at 1; 
WY HSP at 1; LA HSC at 1; NJIT at 3; CO DOT at 1; GHSA at 1; ODU at 1-
2; MO DOT at 1; CA OTS at 1.) Some of these commenters stated that the 
additional costs would divert resources away from other programs. (CO 
DOT at 1; LA HSC at 1; GHSA at 1; ID DOT at 1.) NHTSA understands that 
the new criteria may impose additional costs for some States, 
especially States that will need to conduct observations in more 
counties and at more observation sites. Based on our review of the 
changes required under the new criteria and States' current seat belt 
use surveys approved under the 1998 Uniform Criteria, we do not believe 
that this will significantly increase costs for most States.\3\ 
However, the changes to the Uniform Criteria will yield better data, 
and this will improve the States' identification of low seat belt use 
problem areas and permit more effective targeting of countermeasures to 
increase seat belt use. Accordingly, States will be able to target 
their life-saving programs more effectively, resulting in fewer 
fatalities. For these reasons, we believe that the improved quality and 
reliability of the survey outweighs the additional costs.
---------------------------------------------------------------------------

    \3\ The WA TSC stated that the revised criteria will 
substantially increase its costs, up to $100,000 the first year. (WA 
TSC at 1, 4.) NHTSA does not believe that many, if any, States will 
incur costs of $100,000 to redesign the survey. Based on our 
estimate, we expect that many States will spend tens of thousands of 
dollars to redesign the survey. The CA OTS stated that it expected 
increased costs due to a 50 percent increase in the number of survey 
sites. (CA OTS at 1. See also MO DOT at 1.) It is not clear how CA 
OTS determined that it would need a 50 percent increase in the 
number of observation sites under the new criteria. Because we have 
revised the survey criteria in order to provide States with design 
flexibility, we believe that CA OTS would not need a 50 percent 
increase in the number of observation sites and suggest California 
and other States consult its statistician for survey design 
alternatives. (See discussion in Section III.D.1 below.)
---------------------------------------------------------------------------

    Several commenters suggested that NHTSA provide additional funding 
to assist States or that NHTSA redesign 56 surveys and analyze the data 
from those surveys. (ODU at 1-2; MO DOT at 2; WA TSC at 2, 4.) Although 
NHTSA intends to provide technical assistance to States, including a 
road inventory and a fatality distribution, NHTSA does not have the 
resources to provide States with additional funds, and NHTSA does not 
have the resources to redesign all 56 surveys and analyze the data. 
Currently, all States receive NHTSA grant funds, such as Section 402 
program funds (23 U.S.C. 402), which may be used to design and conduct 
surveys and analyze data. States may also use other grant funds, such 
as Section 406 program funds (23 U.S.C. 406), to redesign and

[[Page 18045]]

conduct surveys. Consequently, NHTSA declines to adopt these 
commenters' suggestion.

C. Definitions (Sec.  1340.3)

    GHSA asked for an explanation of the source of roadway-related 
definitions. (GHSA at 1.) The agency relied on the U.S. Census Bureau's 
TIGER/Line files, Second Edition (2006) for the definition of most of 
the roadway-related terms. Specifically, the definition for access 
ramp, cul-de-sac, vehicular trail, service drive, and traffic circle 
comes from the TIGER/Line files. The TIGER/Line files are typically 
used in conjunction with geographic information system (GIS), or 
similar, software. Because the database of road segments that NHTSA 
will provide to States will be the GIS population of roads, we relied 
on the definitions used in the TIGER/Line files. The other two terms 
(nonpublic road and unnamed road) are not defined in the TIGER/Line 
files, but are defined to reflect a common understanding of these 
terms.
    The TX DOT asked whether the definition of passenger motor vehicle 
included limousines and other for-hire vehicles, whether a pickup truck 
included a wrecker tow vehicle, a flatbed 3 or 4 ton truck or a utility 
service truck, and whether a van included any size or type a van. (TX 
DOT at 3.) In the NPRM, passenger motor vehicle was defined as ``a 
passenger car, a pickup truck, van, minivan or sport utility vehicle.'' 
Generally, most passenger cars, pickup trucks, vans, minivans and sport 
utility vehicles (SUVs) are motor vehicles with a gross vehicle weight 
rating (GVWR) of less than 10,000 pounds (lbs). In the proposal, NHTSA 
intended those vehicles with a GVWR of under 10,000 lbs to be included 
in the seat belt use survey. To clarify this point and in response to 
this comment, we amended the definition of ``passenger motor vehicle'' 
to read as follows: ``A motor vehicle with a gross vehicle weight 
rating of less than 10,000 pounds, including a passenger car, pickup 
truck, van, minivan or sport utility vehicle.'' Accordingly, those 
vehicles, including limousines, for-hire vehicles, wrecker tow 
vehicles, flatbed 3 or 4 ton trucks, utility service trucks and vans 
that are under 10,000 lbs GVWR must be included in the seat belt use 
survey.

D. Selection of Observation Sites (Sec.  1340.5)

1. Sampling Frame: Exclusion
    The agency received many comments regarding the sampling frame 
requirements. It appears that most of these comments reflect a 
misunderstanding of the sampling frame requirements. Much of this 
misunderstanding appears to stem from the fatality-based exclusion at 
the county level, as specified in Sec.  1340.5(a). (E.g., ID DOT at 1; 
Peters & Assoc. at 1-2; IA TSB at 1; MS State Univ. at 1; ND Dot at 1; 
NV DPS at 5; OR DOT at 1; PA DOT at 1; TX DOT at 1; WA TSC at 4-5; WV 
HSP at 1-2; WY HSP at 1; NH HSA at 1.) Many commenters mistakenly 
referred to a ``fatality-based survey'' or a ``fatality-based 
criterion''. (E.g., Peters & Assoc. at 1-2; GHSA at 2; IA TSB at 1; NV 
DPS at 5.) For example, one commenter stated that the switch from a 
population-based to a fatality-based seat belt survey is flawed and 
will produce far less representative results of actual safety belt use 
for a number of reasons: (1) The location of fatalities is not 
necessarily representative of where people live, work and drive; (2) 
fatal crashes are not representative of where injury crashes occur and 
not representative of where property damage crashes occur; and (3) a 
fatality-based survey is not representative of exposure or population, 
which are two critical components of a measurement of seat belt use. 
(IA TSB at 1.) Some commenters asked how site selection can be based on 
both a fatality and county-by-county basis. (E.g., OR DOT at 1; Peters 
& Assoc. at 1.) We believe that these comments capture the general 
misunderstanding among commenters regarding the fatality-based 
exclusion.
    As a general matter, in a survey that covers a large geographic 
area, such as a Statewide seat belt use survey, it may be costly to 
send data collectors to a random sample of observation sites across the 
large geographic area. To reduce travel costs and time of collection, 
the large geographic area is divided into subareas, or primary sampling 
units, and a sample of these primary sampling units is selected. Data 
are then collected within these primary sampling units. For Statewide 
seat belt use surveys, the large geographic area is the State itself, 
and the primary sampling units are counties (or county equivalents). 
Because States believed that the costs were too great to send data 
collectors to a randomly selected sample of observation sites across 
the State, in the 1998 Uniform Criteria, NHTSA allowed the State to 
select a probability-based sample of its counties and then to select 
observation sites within the selected counties in which to count seat 
belt use observations. The selection of counties is called the first 
stage of the sample. A number of States had many small counties with 
little population and road traffic. Thus, the 1998 Uniform Criteria 
allowed States to exclude the smallest counties with a cumulative 15 
percent of the population from the first stage sampling frame, i.e., a 
population-based exclusion.
    Over time, NHTSA became aware that some small counties had 
measurable road traffic because they contained major roads. The traffic 
on these roads resulted in a disproportionate share of the motor 
vehicle related fatalities compared to the population of the county. 
This circumstance was the basis for NHTSA's proposal to change the 
exclusion criteria in the revised criteria from a population-based 
exclusion to a fatality-based exclusion in the first stage sampling 
frame. With this change, counties that have few fatalities may be 
excluded from the seat belt survey. We note, however, States are not 
required to exclude counties from the sampling frame, and may include 
and sample randomly from all counties. (See KS DOT at 1.) Accordingly, 
under the new criteria, the State may identify any set of counties that 
collectively account for 15 percent of the State's passenger motor 
vehicle occupant fatalities, and that set of counties may be excluded 
from the first stage sampling frame.
    The main purpose for allowing any exclusion, whether fatality-based 
or population-based, is to control operational costs. As explained 
above, the purpose of the exclusion is to help States reduce travel 
costs and time of collection by excluding areas where little data are 
likely to be collected. The fatality-based exclusion does not directly 
affect the selection of the actual observation sites within eligible 
counties. In other words, neither the number of fatalities in a county 
nor the specific locations where those fatalities occurred should serve 
as the basis for selecting the observation sites. (See LA HSC at 2.)
    Some commenters stated that shifting from a sampling frame of 
counties accounting for at least 85 percent of the Statewide population 
to one that includes at least 85 percent of the passenger vehicle 
occupant fatalities seems to replace a potentially biased sampling 
frame with one that is almost certainly biased. (E.g., WA TSC at 1-2; 
GHSA at 1-2. See also IACP at 2; NV DPS at 2, 4; ODU at 2; NJIT at 1-
2.) NHTSA believes that, by permitting the systematic exclusion of the 
State's most sparsely populated counties from the sampling frame, the 
1998 Uniform Criteria created an urban bias. While we are not 
eliminating the urban bias, we believe we are reducing it in many 
States by replacing the population-based

[[Page 18046]]

exclusion with the fatality-based exclusion. For some States, the 
change to a fatality-based exclusion may not have any impact on the 
sampling frame. For example, under a population-based exclusion, States 
systematically set aside sparsely populated counties from the sampling 
frame. Therefore, States end up with more urban areas in the first 
stage sampling frame. A fatality-based exclusion is less urban-biased 
with respect to seat belt use because States are not systematically 
eliminating all low population areas, but are required to include those 
low population counties which have enough fatalities to be included in 
the sampling frame. It is not uncommon in many States for a sparsely 
populated county to have high traffic volume, sometimes resulting in 
relatively frequent crashes and deaths. A population-based exclusion 
may eliminate that county while a fatality-based exclusion may keep 
that county in the sampling frame.
    Other variables, such as crash or fatality rates, registered 
vehicles, vehicle miles traveled (VMT), could be used as the basis for 
excluding counties from the sampling frame. (See MS State Univ. at 1.) 
NHTSA decided to use passenger vehicle occupant fatalities in motor 
vehicle crashes as the measure because these other measures are similar 
to population and would result in a similar urban bias. For example, 
vehicle registrations likely are closely correlated with population so 
that a registration-based exclusion probably would produce the same 
urban bias as the current population-based exclusion. On the other 
hand, VMT or VMT-based crash or fatality rates could be used to exclude 
counties in a way that would avoid an urban bias. However, many States 
do not have accurate counts of VMT for all counties. For this reason, 
NHTSA believes that allowing fatality-based exclusion of counties is 
the preferred method of balancing survey efficiency and cost 
considerations while continuing to ensure a representative sample. 
Therefore, no change is made in response to these comments.
    One commenter stated that it is likely that oversampling and 
overweighting the observations in rural counties with high fatality 
rates and low belt use rates will erroneously depress the State's seat 
belt use rate in an attempt to focus attention on problem areas. (WA 
TSC at 2.) The fatality-based exclusion is not an attempt to focus on 
problem areas. Rather, as discussed above, its intent is to help reduce 
the current urban bias and ensure that seat belt use rate estimates are 
more representative. We note that oversampling need not lead to 
overweighting if the weight is calculated properly. In our opinion, 
properly weighted observations will not introduce error into the 
Statewide seat belt use rate estimate.
    Commenters expressed concern that the fatality-based exclusion 
would result in additional counties being included in the sampling 
frame, especially in more rural areas. (NJIT at 1; WA TSC at 2; WY HSP 
at 1; MO DOT at 1; ND DOT at 1; GHSA at 2.) For example, the MO DOT 
stated that the ``fatality based sampling frame'' will result in 62 
counties and 1,426 observation sites being included in the sampling 
frame when the State's current sampling frame includes 20 counties and 
460 observation sites. (MO DOT at 1. See also CA OTS at 1.) We note 
that when more counties are in a sampling frame, more counties are 
eligible for selection, but this does not necessarily mean that more 
counties will be selected. Although it is not clear how the MO DOT 
estimated the number of counties and observation sites, we believe that 
the estimate may be a result of a misunderstanding of the fatality-
based exclusion as discussed above, and we do not expect that Missouri 
or any State would be required to more than triple the number of 
observation sites at which it collects data. Some States will need to 
increase the number of counties included in their county sampling 
frame. This may result in an increase in the number of counties 
selected in the first stage of their sample, which, in turn, may impose 
additional costs for these States. However, we do not believe it would 
approach the magnitude described by MO DOT. Based on our review of 
current seat belt survey designs, we do not believe that change to a 
fatality-based exclusion will significantly increase costs in most 
States. Because these new Uniform Criteria were designed to give States 
flexibility in designing seat belt use surveys, States should work with 
their survey statisticians to develop a design that best meets their 
needs and circumstances.
    Some commenters stated that the shift to a fatality-based exclusion 
may impact low population States, where fewer motor vehicle fatalities 
occur, and suggested that five years of fatality data should be 
averaged. (ND DOT at 1; ME DPSC at 1; WY HSP at 1; NH HSA at 1.) We 
recognize that in small rural States, there can be sharp annual 
fluctuations in the numbers and distribution of fatalities. 
Accordingly, after careful consideration, we have decided to amend the 
rule to allow States the option to average three, four or five years of 
FARS data to determine passenger vehicle occupant fatalities. We 
believe that allowing States this flexibility will reduce the 
potentially disproportionate impact of any single multi-fatality crash 
in any given year. Accordingly, we have amended the rule in response to 
these comments.
    Several States asked for clarification about the kinds of 
fatalities that are to be counted for the fatality-based exclusion. Two 
commenters asked for clarification about which occupants and which 
vehicles counted in the fatality-based exclusion. (OR DOT at 1; WV HSP 
at 1.) Two commenters suggested that the sampling frame should be 
limited to unrestrained fatalities. (NY TSC at 1-2; PA DOT at 1.) To 
clarify, the county-by-county fatality counts that will be used to 
identify counties that may be excluded from the sampling frame will be 
based on passenger motor vehicle occupant fatalities only (and not on 
commercial vehicle occupant, motorcycle, bicycle or pedestrian 
fatalities) that occur in each county on roads to which the public has 
the right of vehicular access. We recognize that counts of unrestrained 
fatalities could be used as the basis for determining which counties 
may be excluded from the sampling frame. However, especially in 
sparsely populated States with relatively low fatality totals, the 
counts of unrestrained fatalities even when using three, four or five 
year totals may produce unstable distributions. For consistency, NHTSA 
believes that all States should use counts of all passenger motor 
vehicle fatalities to determine which counties may be excluded from the 
sampling frame. As noted before, the purpose of the fatality exclusion 
is not to direct data collection to specific locations of fatalities 
but to reduce the bias toward urban areas. The agency declines to adopt 
these commenters' suggestions.
    The LA HSC commented that if crashes are used in lieu of population 
as a factor in determining site location, States should be permitted to 
account for serious injury crash data. (LA HSC at 2.) Another commenter 
recommended that the rule be changed to measure ``fatal crashes'' 
instead of ``crash fatalities.'' (IACP at 1.) As stated above, neither 
the number of fatalities in a county nor the specific locations where 
those fatalities occurred is a factor in selecting the actual 
observation sites. The fatality counts are used solely to determine 
which counties a State may exclude from its sampling frame in order to 
control operational costs. NHTSA believes that fatality counts serve as 
an adequate basis for that determination. We do not believe that counts 
of serious injuries or of fatal crashes (in lieu of crash fatalities) 
would

[[Page 18047]]

provide additional value in the identification of counties that may be 
excluded from the sampling frame. We decline to change the rule in 
response to these comments.
    One commenter asked if day and night differences in fatalities will 
be considered in selecting observation sites. (NV DPS at 4.) As noted 
above, we believe that the commenter misunderstood the purpose of the 
fatality-based exclusion. The actual fatalities do not determine where 
the observation sites are located. Rather, the three-, four- or five-
year fatality counts will be used to allow the State to exclude 
counties that make up 15 percent of the State's passenger vehicle 
occupant fatalities. Both day and night passenger vehicle occupant 
fatalities will be counted in determining the fatality counts. With 
this clarification, no change to the rule is made.
    One State asked if States could have the option to use their own 
non-FARS fatality data because the most recent FARS data are often less 
current than State's own traffic fatality counts. (WI State Patrol at 
1.) In the preamble to the NPRM, NHTSA stated that the agency would 
provide States with county-by-county passenger motor vehicle occupant 
fatality counts for the relevant time period. We believe that allowing 
States to use their own fatality data would have little or no impact on 
defining the State's sampling frame. After careful consideration, we 
have decided to allow States the option to use the NHTSA-provided 
fatality data or their own fatality data for the most recent three, 
four or five years, provided that the State fatality data reflect the 
FARS definitions and are approved by NHTSA. We have revised the Final 
Rule accordingly.
    One commenter stated that under the existing rule, the population 
and average VMT based sampling criteria took into account an ``infinite 
sample size,'' but with the proposed fatality-based sampling, ``the 
fatalities become the universe.'' (NV DPS at 4.) The commenter further 
stated that the statistical concepts related to the ``central limit 
theorem'' and the ``normal distribution'' might lose their ``essence,'' 
and that we cannot derive statistical results. Id. The commenter asked 
if it was necessary to look into the ``finite population theory for 
sampling.''
    This commenter appears to assume, incorrectly, a change from 
population-based exclusion to fatality-based exclusion, in which the 
central limit theorem (which states that as the sample size becomes 
larger, the sample mean will have an approximately normal distribution) 
would cease to have applicability because the sample size would be 
finite. As discussed above, the proposal did not change to fatality-
based exclusion. It changed only the way counties are excluded from the 
sampling frame. In other words, the proposal did not require 
observations to be conducted at locations of fatal crashes. In fact, 
locations of fatal crashes should not serve as the basis for selecting 
actual observation sites. Under both the 1998 Uniform Criteria and the 
proposal, both population and sample sizes are finite, not infinite. 
This does not mean that the central limit theorem cannot be applied to 
the seat belt use rate estimate. In a seat belt use survey, the sample 
mean is the estimated seat belt use rate. As the sample size in a 
State's seat belt use survey becomes large enough, the central limit 
theorem would still be valid, i.e., the estimated seat belt use rate 
will have an approximately normal distribution.
    Several commenters stated that the change from a population-based 
exclusion to a fatality-based exclusion would make it difficult for 
States to compare the seat belt survey results to previous years' 
estimates. (NY TSC at 1; PA DOT at 1; GHSA at 2; IA TSB at 1; TX DOT at 
2. See discussion in Section III.A above.) While the change in the 
sampling frame exclusion may make comparing estimates from previous 
years more challenging, we believe that the data still remains 
valuable. The new seat belt use rate estimates will be more 
representative of the actual seat belt use rate in the State than 
previous estimates. We believe that the need for more accurate and 
reliable data outweighs the challenges in comparing survey results. (As 
noted above, this is not a change from a population-based survey to 
fatality-based survey. Rather, the change only affects the exclusion 
from the sampling frame that is allowed for controlling operational 
costs.)
2. Sampling Frame: Database of Roads
    Some commenters supported the requirement that the database of road 
inventories includes all roads with a few exceptions, and agreed that 
NHTSA should provide the database to the States. (WA TSC at 3; Peters & 
Assoc. at 2; NV DPS at 6.) Two commenters requested more specific 
information about the database of road inventories. (ND DOT at 1; GHSA 
at 2.) The commenters asked whether the NHTSA-provided database would 
be a GIS population of roads, what variables would be included in the 
database, and whether roads on tribal lands and national parks would be 
included. The road database that NHTSA intends to provide will include 
road type and location, but is unlikely to include vehicle miles 
traveled. Roads on tribal lands and national parks are included in the 
database. As discussed in more detail below, NHTSA has amended the rule 
to allow the exclusion of rural local roads in counties that are not 
included in a Metropolitan Statistical Area (MSA) and, as a result, 
many roads in tribal lands and national parks may be excluded. No 
change to the rule is made in response to these comments.
    One commenter requested clarification on whether the State could 
use its own map, aerial photos or satellite images in site selection. 
(WI State Patrol at 2.) As stated in the rule, a State may use its own 
map, aerial photos or satellite images if it is approved by NHTSA, as 
provided in Sec.  1340.5(a)(2).
    One commenter asked whether the State must abandon the practice of 
making seat belt use observations only at stop lights or stop signs. 
(WI State Patrol at 2.) As specified in the proposal, the sampling 
frame may not be limited only to roads having a stop sign or stop 
light. Accordingly, States may not confine the data collection to stop 
lights and stop signs. Such a practice would exclude observation of a 
large universe of road segments, and would produce a biased seat belt 
use estimate. Consequently, the agency declines to adopt the suggestion 
in response to this comment.
    Another commenter agreed with the proposed exclusions except for 
the exclusion of access ramps to interstate roadways. (Peters & Assoc. 
at 2.) GHSA requested an explanation of the road exclusions. (GHSA at 
2.) As stated in the NPRM, the agency excluded these categories of 
roads for reasons of safety and practicality. In addition, some of 
these road categories are not likely to be in the database of road 
inventories, and they are low traffic volume roads that will not affect 
the overall estimate of the seat belt use rate. We note that a State 
may choose to exclude the roads identified in Sec.  1340.5(a)(2)(iii), 
but is not required to do so. Therefore, a State may include access 
ramps in its database of road inventories. With this clarification, no 
change to the rule is made.
    Several commenters expressed concern that the proposed road 
coverage requirement would require States, especially those with more 
rural areas, to sample on road segments with very little traffic 
volume. (ID DOT at 1; IL DOT at 1; NH HSA at 1; IACP at 1; ME DPSC at 
1; GHSA at 1-2.) NHTSA researched this issue and found that while local 
roads (as defined by the Federal Highway Administration) have

[[Page 18048]]

more than two-thirds of road miles in rural areas, these roads 
experience only 13 percent of the VMT in rural areas. Sending data 
collectors to observation sites on some of these local roads might 
result in few, or even no, observations and would increase costs to the 
State. However, NHTSA determined that excluding all local roads in 
rural areas would have a measurable impact on the accuracy of the seat 
belt use rate estimate.
    FHWA has classification standards for roads (``Functional 
Classification Guidelines'') that all States use. In FHWA's Functional 
Classification Guidelines, ``local roads'' are a category of roads 
which are not collectors or arterials, but permit travel between end 
points of a trip. FHWA further classifies local, collector and arterial 
roads as being in an urban or rural area. Based on our review of 
available data, allowing States to exclude all ``rural local roads'' 
from the sampling frame would significantly impact the seat belt use 
rate estimate because a substantial number of rural local roads are in 
areas that have high traffic volumes and potentially high fatality 
rates. For this reason, NHTSA determined that allowing a more limited 
exclusion of rural local roads would be more appropriate.
    Pursuant to 44 U.S.C. 3504(e)(3), 31 U.S.C. 1104(d), and Executive 
Order No. 10253, the Office of Management and Budget (OMB) defines 
Metropolitan Statistical Areas (MSAs) and other statistical areas. 
(E.g., OMB Bulletin No. 10-02.) MSAs are statistical areas that include 
multiple counties and county-equivalents with at least one urbanized 
area that has a population of at least 50,000. See 75 FR 37246, 37252 
(June 28, 2010). Rural local roads in counties or county-equivalents 
that are not part of an MSA are those roads that are likely to have 
very low traffic volume. Consequently, excluding rural local roads in 
non-MSA areas from the sampling frame would have a limited impact on 
the seat belt use rate estimate, but would significantly reduce data 
collection costs. Therefore, NHTSA has amended the Final Rule to allow 
an additional exclusion of rural local roads that are not included in 
an MSA.
3. Sampling Selection Requirements
    A number of commenters requested clarification on the selection of 
observation sites, as provided in Sec.  1340.5(b). (E.g., TX at 2; 
Peters & Assoc. at 2; ND DOT at 1.) One commenter asked about the 
selection of roads and assignment of weights in order to avoid 
oversampling one road type. (GHSA at 2. See also NV DPS at 6.) We 
believe that this commenter is seeking clarification of two issues--(1) 
how should the road inventory be stratified by functional 
classifications for purposes of this selection; and (2) how should the 
observations at each observation site be weighted to ensure an accurate 
estimation of seat belt use rate. (See also WY HSP at 3, 11; MO DOT at 
2; NY TSC at 2.) One commenter stated that if all roads in the State 
have an equal probability of being selected, streets and other roads 
with relatively low traffic volumes are likely to be overrepresented in 
the sample. (NY TSC at 2. See also NJIT at 1-2.)
    States are not required to stratify their sampling frame, whether 
by road type or by another variable. The only requirement is that the 
selection of observation sites be probability-based, i.e., each 
observation site should have a known probability of selection. A State 
may draw a simple random sample without stratification from the entire 
road sampling frame, i.e., from the listing of all road segments within 
a county selected in the first stage of sampling. A State also may 
stratify the sampling frame in a variety of ways, using such variables 
as road classification or VMT, and then draw a probability based sample 
of observation sites from each stratum. Although NHTSA believes that 
stratifying road inventories by functional classification and selecting 
road segments with probability proportional to VMT within these strata 
is good practice, there are other valid approaches to forming a 
probability sample of observation sites.
    Regardless of the method used for selecting observation sites, once 
observations are made, the data must be weighted in a manner consistent 
with the survey design. One commenter stated that because the State 
does not have VMT for all local roads, it would be forced to exclude 
these roads from the sampling frame. (LA HSC at 1.) States are not 
permitted to exclude systematically all local roads from the sampling 
frame. If the State does not have VMT for some or all eligible road 
segments in the selected counties, the State must use some other method 
for designing and selecting its sample. The survey statistician should 
be able to help States select an appropriate method for weighting 
observation sites. With this clarification, no change to the rule is 
made.
    Several commenters requested additional information on the number 
of observation sites States need to include in their survey. The WY HSP 
asked whether States will be given any guidelines as to the recommended 
number of observation sites to be selected based on the number of 
counties. (WY HSP at 3.) The MO DOT requested that provisions be added 
for States to randomly select a representative group of counties from 
those representing 85 percent of the State's fatalities, similar to the 
table provided in the appendix to the current criteria. (MO DOT at 1.) 
The commenter further requested that the rule specify the required 
number of road segments to be sampled in each county. (MO DOT at 2.) 
The OR DOT requested a formula for determining the total number of 
sampling sites that would be needed. (OR DOT at 1.)
    NHTSA does not intend to provide a table or formula specifying the 
number of observation sites per county based on the number of road 
segments available within that county. One table or formula will not 
optimally serve to determine the number of observation sites for all 
survey designs. We revised the Uniform Criteria to give States the 
flexibility to design a survey in a manner that best meets the specific 
environment in each State. States should rely on their survey 
statistician to develop a survey design that will meet the Uniform 
Criteria and meet the State's needs. The survey statistician can help 
the State determine the necessary sample sizes for selection of 
counties at the first stage and selection of observation sites (road 
segments) within the selected counties. NHTSA is developing a sample of 
an acceptable survey design to assist the States' redesign efforts, and 
will post the sample survey design on NHTSA's Web site. Accordingly, we 
decline to adopt these commenters' suggestion.
4. Substitution and Resecheduling of Observation Sites
    Generally, commenters stated that the agency's proposal in Sec.  
1340.5(c) regarding protocols when observation sites are not available 
was reasonable. (WA TSC at 3; Peters & Assoc. at 3.) One commenter 
suggested that pre-selecting alternate observation sites before the 
start of data collection would be more practical. (Peters & Assoc. at 
3.) The pre-selection of alternate observation sites is not precluded 
under the Uniform Criteria. The alternate observation sites must be in 
the same county and the same road classification as the observation 
site the State is replacing. Another commenter asked if it would be 
acceptable to combine both options--returning to the observation site 
on the same day of the week and at the same time of the day and 
selecting an alternate observation site--as part of the State's 
protocol when an observation site is temporarily unavailable. (TX DOT 
at 2.) States may include one or both

[[Page 18049]]

options as part of their protocol in their survey design. With this 
clarification, no change to the rule is made.
    The commenter stated that requiring the State to return to an 
observation site at the same time and day of the week if an observation 
site is missed, especially if the observation site is hundreds of miles 
away, would increase commuting time and other costs. (IACP at 2. See 
also ODU at 3.) As stated in the NPRM, if conditions preclude data 
collection at an observation site at the scheduled time and day, States 
may elect to return to the observation site at the same time and day or 
collect data from preselected alternate observation sites to replace 
the observation site that is unavailable. See Sec.  1340.5(c). If 
adverse weather precludes data collection, it is likely to affect data 
collection at multiple observation sites, especially if observation 
sites are cluster sampled. With adverse weather conditions, States 
generally should be able to anticipate whether the conditions would 
affect data collection before data collectors travel to the observation 
sites, and therefore, should be able to plan accordingly to mitigate 
commuting time and costs. States are encouraged to consider these 
issues and develop a protocol that best fits the conditions in its 
State. The agency makes no change to the rule in response to this 
comment.
5. Precision
    The agency received a number of comments regarding the standard 
error in Sec. Sec.  1340.5(d) and 1340.9(g). Some commenters agreed 
with the change. (WY HSP at 2-3; WA TSC at 3; IL DOT at 1.) Others 
stated that the change in the precision requirement would require a 
larger sample size or longer observation times, and this would result 
in higher survey costs. (Peters & Assoc. at 1, 3, 5; TX DOT at 2; GHSA 
at 2; NV DPS at 7; WV HSP at 2; ND DOT at 1; NH HSA at 1.) One of these 
commenters further stated that reducing the standard error by half 
would require a four-fold increase in sampling size, and asked whether 
it would be possible to get four times the current sample size with the 
same observation time. (NV DPS at 7.) This commenter may have 
misunderstood the change in the precision requirement--the 1998 Uniform 
Criteria specify that the relative error not exceed 5 percent while the 
proposed rule specifies that the standard error not exceed 2.5 
percentage points. The standard error is an absolute measurement 
whereas the relative error measures the standard error as a fraction of 
the actual seat belt use estimate. Unlike the relative error, the 
standard error will not change regardless of a State's seat belt use 
rate estimate. A standard error holds all States to the same standard.
    Our review of States' current surveys indicates that most States 
will be able to meet the required standard error of 2.5 percentage 
points with sample sizes comparable to their current surveys. 
Therefore, we believe that most States will not have to add a 
significant number of observation sites, and costs will not be 
significant. We also believe that any additional costs are outweighed 
by the improved quality and reliability of the survey data.
    One commenter also stated that the precision calculation is made 
after the data are collected, and that an inadequate precision would 
require returning to some number or all of the observation sites to 
collect additional data, which could significantly increase the costs. 
(Peters & Assoc. at 3.) The commenter is correct that the final 
precision estimate cannot be made until after the data are collected. 
While a State would have to collect additional data if the precision is 
above 2.5 percentage points, the State would not have to return to all 
the observation sites to collect additional data. We note that at the 
survey design stage, the State may use information from its current 
survey or a similar survey from another State to estimate the number of 
observation sites that may be needed to provide a reasonable assurance 
that the precision requirement will be met. Consistent with standard 
practice in survey collection, States should select a sufficient number 
of observation sites to account for issues that may affect the standard 
error. We believe that a survey statistician should be able to help the 
State determine the proper sample size for the required precision. The 
agency declines to change the rule in response to these comments.
    A commenter stated that the change in precision requirement will be 
difficult and expensive to achieve on rural roads. (NJIT at 2.) 
According to this commenter, fewer interstate and freeway roadways will 
be selected for performing data collection, which will lead to more 
roads of lower classifications and lower volumes being selected for 
observation. Id. The commenter further stated that this will result in 
longer time periods for data collection and in some cases require more 
than one visit to a location for data collection. Id. The precision 
requirement applies to the entire survey--not to individual observation 
sites. As stated above, for most States, we do not believe that the 
change will substantially affect the number of observation sites that 
will be required. Consequently, the periods of data collection should 
not substantially change for most States. We note that NHTSA is 
revising the proposal to allow States to exclude rural local roads in 
counties that are not included in an MSA from the sampling frame, which 
will help mitigate the concerns of this commenter. Accordingly, no 
further change to the rule is made in response to this comment.
    One commenter stated that consistency in training and observation 
would be a much better place to invest resources than in reducing 
sampling error. (NH HSA at 1.) NHTSA assumes the commenter is asserting 
that improved training would reduce survey sampling error. There are 
two kinds of errors--measurement errors and sampling errors. 
Consistency in training to improve observation skills can reduce 
measurement errors, i.e., the accuracy of the observations. However, it 
will not reduce sampling error, which is a result of a subset of the 
target population is being observed. Consequently, the agency declines 
to adopt this commenter's suggestion.

E. Assignment of Observation Times (Sec.  1340.6)

    Two commenters expressed support for the proposed observation 
times. (WA TSC at 3; Peters & Assoc. at 3.) One commenter stated that 
requiring data collection until 6 p.m. could pose difficulties during 
late fall and winter, when it gets dark by 5 p.m. (IACP at 1.) In the 
NPRM, the agency proposed that data collection must take place during 
daylight hours, not all hours, between 7 a.m. and 6 p.m. Accordingly, 
States would not be required to collect data at an observation site 
during non-daylight hours even if they fall between the hours 7 a.m. 
and 6 p.m. No change to the rule is made in response to these comments.
    Two commenters stated that requiring random assignment of the day 
of the week for observations would increase costs, especially if data 
collectors were sent to opposite corners of the State in a 24-hour 
period. (IACP at 2; ODU at 3.) While the NPRM proposed random 
assignment of the day of the week for observations, it also proposed 
allowing States to cluster sample or group observation sites in close 
geographic proximity in order to reduce the costs of random assignment 
of observation sites. (See also OR DOT at 1.) This would reduce the 
need for data collectors to be sent to opposite corners of the State in 
a 24-hour period.
    These commenters also suggested treating weekdays as equal and

[[Page 18050]]

weekends as equal. (IACP at 2; ODU at 3.) NHTSA does not have data to 
support the assumption that there is no seat belt use rate difference 
between the days of the week and between Saturday and Sunday. We 
believe that allowing States to cluster sample observation sites in 
close proximity should sufficiently reduce the operational costs of 
random assignment of the day of the week. Therefore, NHTSA declines to 
adopt this recommendation.
    The NV DPS asked how many observation sites can be grouped together 
into geographical clusters. (NV DPS at 7.) NHTSA did not propose to 
limit the number of observation sites that can form a cluster. As long 
as the State can allocate an appropriate time period for data 
collection at each observation site, those observation sites may be 
cluster sampled. No change to the rule is made in response to this 
comment.

F. Observation Procedures (Sec.  1340.7)

    1. Data collection dates. The TX DOT commented that the proposal 
did not specify that the surveys should be conducted uniformly after 
Click It or Ticket or Memorial Day Monday. (TX DOT at 2.) This 
commenter recommended a wider window of survey time, such as May 1 
through June 30. Id. In the NPRM, the agency did not propose a change 
from the requirement in 1998 Uniform Criteria that all observations 
take place during the calendar year, i.e., January 1 to December 31. 
Although most States choose to conduct seat belt use surveys after 
Click It or Ticket or Memorial Day Monday, States may conduct surveys 
anytime during the calendar year. No change to the rule is made in 
response to this comment.
    2. Roads with two-way traffic. Peters & Assoc. commented that on 
low volume two-way streets, limiting an observer to observing one 
direction of traffic flow would result in unnecessary additional survey 
cost. (Peters & Assoc. at 4.) NHTSA believes that consistent methods 
for data collection should be applied at all observation sites, 
regardless of the volume of traffic. Moreover, requiring the data 
collector to observe traffic in one direction will help reduce 
measurement error. Accordingly, the agency declines to change the rule 
in response to this comment.
    3. Vehicle coverage. The agency received a number of comments 
regarding the proposal's vehicle coverage requirements. The commenters 
were generally supportive of the proposal, but a few questioned the 
inclusion of certain vehicles. Several commenters appeared to 
misunderstand the requirements, and some commenters requested 
clarification.
    One commenter stated that the proposal did not address State seat 
belt law exemptions for certain vehicles and recommended that all 
vehicles operated on a public roadway should be included in the survey 
regardless of a State's exemptions. (LA HSC at 2.) In contrast, two 
commenters questioned the inclusion of vehicles that are exempt under 
the State's seat belt law because it would not provide an accurate 
measure of compliance. (NY TSC at 2; GHSA at 2.) In the NPRM, the 
agency stated that all passenger motor vehicles must be included in the 
survey, including vehicles that are exempt by the State's seat belt 
law. The purpose of the seat belt use rate survey is not to determine 
compliance with the State's seat belt law, but rather to estimate the 
actual seat belt use of drivers and right front passengers. 
Consequently, the agency makes no change to the rule in response to 
these comments.
    One commenter supported the inclusion of ``passenger vehicles for 
commercial use'' in the seat belt use survey. (WY HSP at 2.) Three 
commenters requested clarification of the term ``commercial passenger 
motor vehicle.'' (OR DOT at 1; TX DOT at 3; GHSA at 2.) Earlier in this 
notice, we clarified that passenger motor vehicles include a passenger 
car, pickup truck, van, minivan or sports utility vehicle with a GWVR 
of less than 10,000 lbs. Data from motor vehicles over 10,000 lbs GWVR 
need not be included in this survey. As stated in the preamble of the 
NPRM, data must be collected for passenger motor vehicles being used 
for commercial purposes. In other words, data from such passenger motor 
vehicles as taxis, flower delivery vans, and pizza delivery cars that 
are under 10,000 lbs GVWR must be included in the seat belt use survey. 
To clarify this point, in Sec.  1340.7(c), the agency has amended the 
phrase ``commercial passenger motor vehicles'' to read ``passenger 
motor vehicles used for commercial purposes.''
    Three commenter