[Federal Register Volume 63, Number 169 (Tuesday, September 1, 1998)]
[Rules and Regulations]
[Pages 46389-46394]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23410]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
23 CFR Part 1340
[Docket No. NHTSA-98-4280]
RIN 2127-AH46
Uniform Criteria for State Observational Surveys of Seat Belt Use
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Interim final rule; request for comments.
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SUMMARY: This document establishes uniform criteria for State seat belt
use surveys that are to be conducted in connection with a new Federal
grant program. Section 157 of Title 23, United States Code, directs the
Secretary of Transportation to allocate funds to States that achieve a
seat belt use rate that exceeds, for the past two years, the national
average use rate, or that exceeds the highest seat belt use rate
achieved by the State in certain designated previous years. For
calendar years 1998 through 2001, the new law requires the seat belt
use rate submitted by the States to be consistent with measurement
criteria established by the Secretary. This document sets forth the
criteria to be used by the States to determine their seat belt use
rates under this program, starting with surveys conducted in calendar
year 1998. These uniform criteria replace the Guidelines for State
Observational Surveys of Safety Belt and Motorcycle Helmet Use, which
are rescinded by this document.
DATES: This interim final rule is effective on September 1, 1998.
Comments concerning this rule are due no later than January 29, 1999.
ADDRESSES: Comments should refer to the docket number set forth above
and be submitted in writing to the Administrator, National Highway
Traffic Safety Administration, Room 5220, 400 Seventh Street, SW,
Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: The following persons at the National
Highway Traffic Safety Administration, 400 Seventh Street, SW,
Washington, DC 20590: For program issues, Joan Catherine Tetrault,
State and Community Services, NSC-01, (202) 366-2674; For legal issues,
John Donaldson, Office of the Chief Counsel, NCC-30, (202) 366-1834.
SUPPLEMENTARY INFORMATION:
New Seat Belt Incentive Grant Program
Section 1403 of the recently enacted Transportation Equity Act for
the 21st Century (Pub. L. 105-178) added a new Section 157 to Title 23
of the United States Code (replacing a predecessor Section 157 ). The
new section authorizes a State seat belt incentive grant program
covering fiscal years 1999 through 2003. Under this program, the
Secretary of Transportation is directed to allocate funds to the States
(beginning in fiscal year 1999) based on their seat belt use rates.
Today's rule promulgates the Uniform Criteria for State Observational
Surveys of Seat Belt Use (hereafter, Uniform Criteria) to provide
guidance to the States on the seat belt use rate information to be
submitted
[[Page 46390]]
under this new program for calendar year 1998 and beyond.
Section 157 requires the Secretary to allocate funds to States that
achieve a seat belt use rate in the preceding two years that is higher
than the national average use rate or, failing that, a seat belt use
rate that is higher than the highest seat belt use rate achieved by the
State during specified previous calendar years. (Section 157 contains
another provision for allocation of grant funds, based on innovative
projects, but that provision is not addressed in today's notice.) In
order to make the calculations necessary to allocate funds under this
provision, State seat belt use rate information extending back to
calendar year 1996 is needed. For calendar years 1996 and 1997, seat
belt use rate information submitted by the States is required to be
weighted by the Secretary to ensure national consistency in methods of
measurement. Beginning in calendar year 1998, States must measure seat
belt use rates following criteria established by the Secretary, to
ensure that the measurements are ``accurate and representative.'' In
accordance with that mandate, this interim final rule establishes
uniform criteria for States to follow in conducting surveys of seat
belt use, starting with surveys conducted in calendar year 1998.
(Details concerning the procedures the agency will follow in evaluating
and adjusting seat belt use rate information to ensure that it is
accurate and representative and in making the allocation of funds will
be published in the near future in a separate Federal Register
document.)
State Seat Belt Use Surveys
The Uniform Criteria published today incorporate, in large part,
the Guidelines for State Observational Surveys of Safety Belt and
Motorcycle Helmet Use (57 FR 28899, June 29, 1992) (hereafter,
Guidelines) that relate to seat belts. However, the new criteria differ
in one important respect. Section 157 requires the determination of
seat belt use rate to be based on ``passenger motor vehicles,'' a
category that includes passenger cars, pickup trucks, vans, minivans,
and sport utility vehicles. Consequently, the criteria incorporate the
statutory requirement that measurements include the seat belt use rate
of occupants of these vehicles. A number of States have not included
these vehicles in past seat belt surveys.
Another, more minor respect, in which these Uniform Criteria differ
from the Guidelines, is that the observation of child restraint use is
not included in the survey. The agency has removed this requirement
because Section 157 does not include child restraint devices within the
definition of seat belts.
Section 157 requires that measurements of seat belt use rates be
``accurate and representative.'' Consequently, these Uniform Criteria
clarify the Guidelines in other respects. The agency has made clear
that the surveys must include observation of both drivers and front
seat outboard passengers (not simply consider them ``eligible'' for
observation, as provided in the Guidelines). In addition, measurements
of seat belt use must be taken completely within the calendar year for
which the seat belt use rate is reported. Finally, beginning with
surveys conducted during calendar year 1999, both in-state and out-of-
state vehicles must be counted, to improve the representativeness of
measurements. This latter requirement is being phased in next year to
provide the States necessary flexibility, in view of time constraints
associated with the late enactment of TEA-21. These clarifications,
together with other procedures the agency expects to publish in the
near future in the Federal Register (further discussed below), will
ensure consistency and fairness in the allocation of funds.
NHTSA is recommending, in this notice, that seat belt use data be
collected so as to enable separate identification for passenger cars
and other covered vehicles, and separate identification for drivers and
front-seat outboard passengers within these vehicle groups. NHTSA
believes that this separation, although not a requirement, will produce
useful information for the States, the agency, and others to evaluate
trends in seat belt use.
In other particulars, these Uniform Criteria track the Guidelines.
For example, the important requirement that surveys have a probability-
based design has been retained. So, too, have the requirements that
data be collected through direct observation of seat belt use; that the
relative error of the estimate of seat belt use not exceed five
percent; that counties or other primary sampling units totaling at
least 85 percent of the State's population be eligible for inclusion in
the sample; and that all daylight hours for all days of the week be
eligible for inclusion in the sample. The new criteria continue to
require all sample design, data collection and estimation procedures to
be well documented. The appendix, containing a sample design that
satisfies these criteria, is also retained for useful reference. These
and other provisions, continued in today's rule, were previously
published for comment in connection with the Guidelines.
In a separate Federal Register document to be published in the near
future, the agency will explain the process it plans to follow in
reviewing and evaluating surveys submitted by the States in accordance
with today's rule, in determining the national average seat belt use
rate, and in making allocations of funds. In that document, the agency
may consider applying adjustment factors to survey information
submitted by the States before making allocations of funds, to further
ensure that seat belt use measurements are accurate and representative.
Assistance in Developing Surveys
The agency stands ready to assist States in their efforts to
develop probability-based observational surveys that satisfy the
requirements of Section 157 and these uniform criteria. Each NHTSA
Regional Office has a data contractor available to provide technical
assistance to the States upon request. States that have not yet
conducted surveys for calendar year 1998 that satisfy these criteria
may wish to submit proposed survey designs to NHTSA for review, in
order to verify that the survey design satisfies these new criteria.
This may be especially helpful for States that have not received
approval of the similar surveys that were required for award of grant
funds under the Guidelines.
State Eligibility for Grant Funds
The Uniform Criteria published today are effective immediately.
States must become promptly familiar with these criteria because they
apply to surveys required to be conducted during the current calendar
year. States that fail to conduct a calendar year 1998 survey in
accordance with these criteria will not be eligible, during fiscal year
2000 and possibly beyond, for Section 157 grant funds that are based on
the submission of seat belt use rate information.
The Uniform Criteria are limited in scope to the substantive
requirements related to State observational surveys. The agency expects
to publish in the near future, in a separate Federal Register document,
details concerning the procedures the agency will follow in evaluating
seat belt use rate information and in making the allocation of funds.
However, in order to provide the States with as much planning
flexibility as possible in light of the imminence of the requirements
concerning calendar year 1998 surveys, brief information about
submission and review procedures is provided here.
[[Page 46391]]
The agency anticipates that review procedures for surveys will
remain essentially unchanged from those that applied under the
Guidelines. Specifically, States seeking to qualify for an allocation
of Section 157 funds based on their seat belt use rate will submit the
documentation of their survey design described under the
``Documentation'' section of these uniform criteria for review by the
agency. Based on the documentation submitted, NHTSA will determine
whether the survey meets the requirements of these criteria.
Pending the publication of specific procedural guidance in the
Federal Register, States that have not yet conducted a survey for
calendar year 1998 are encouraged to seek pre-approval of their survey
documentation by NHTSA. States that have conducted a survey for
calendar year 1998 are also encouraged to submit survey documentation
for review by NHTSA, to confirm that the survey they have conducted
does, in fact, conform to these criteria. This will avoid the situation
where non-compliance is discovered too late to conduct another survey
during calendar year 1998.
Previous Survey Guidelines Rescinded
With the publication of these Uniform Criteria for State
Observational Surveys of Seat Belt Use, the agency is simultaneously
rescinding the Guidelines. The agency published these latter guidelines
to describe survey requirements for States seeking to receive grants
under Section 153 of Title 23, United States Code, a grant program
which is no longer funded.
Regulatory Analyses and Notices
Executive Order 12612 (Federalism)
This action has been analyzed in accordance with the principles and
criteria contained in Executive Order 12612, and it has been determined
that it does not have sufficient Federalism implications to warrant the
preparation of a Federalism assessment. While it concerns a new State
grant program, this action does not impose any major new requirements
on the States. Rather, it makes minor changes to survey procedures that
have already been used by many States in a previously authorized grant
program and for other purposes.
Executive Order 12778 (Civil Justice Reform)
This rule does not have any preemptive or retroactive effect. It
merely revises existing requirements imposed on States to reflect the
statutory requirements of a new grant program. The enabling legislation
does not establish a procedure for judicial review of final rules
promulgated under its provisions. There is no requirement that
individuals submit a petition for reconsideration or pursue other
administrative proceedings before they may file suit in court.
Executive Order 12866 (Regulatory Planning and Review) and DOT
Regulatory Policies and Procedures
This rulemaking action was reviewed under Executive Order 12866,
``Regulatory Planning and Review.'' The action has been determined to
be ``significant'' under Executive Order 12866 and under the Department
of Transportation Regulatory Policies and Procedures because it is
likely to result in significant economic impacts. A Final Economic
Assessment (FEA) is being prepared for today's rule and for a companion
rule, to be published in the near future, that establishes the
procedures for allocating funds under the grant program authorized by
23 U.S.C. 157. A copy of the FEA, describing the economic effects in
detail, will be placed in the docket for public inspection when the
companion rule is published.
Following is a summary of the cost and benefit information for this
rule. The total annual cost of conducting surveys following the
procedures of this rule (if each State conducted one) is estimated to
be $1.9 million. A State may be eligible for an allocation of funds
during each of fiscal years 2000 through 2003 if it conducts a survey
of seat belt use during each of calendar years 1998 through 2001, in
accordance with the procedures under this rule. Allocations available
to the States total $92,000,000 for fiscal year 2000, $102,000,000 for
fiscal year 2001, and 112,000,000 for each of fiscal years 2002 and
2003. An allocation totaling $82,000,000 is available for fiscal year
1999, but that allocation is dependent on criteria other than the
survey procedures required under this rule. Depending on the results of
State surveys, some funds may remain unallocated, and will be allocated
under other procedures. Details of the procedures for allocating all
funds will be published in another Federal Register document in the
near future.
Regulatory Flexibility Act
In compliance with the Regulatory Flexibility Act (5 U.S.C. 601 et
seq.), the agency has evaluated the effects of this action on small
entities. We hereby certify that this action will not have a
significant economic impact on a substantial number of small entities.
States are the recipients of any funds awarded under the Section 157
program, and they are not small entities.
Paperwork Reduction Act
On August 10, 1998, the Department of Transportation submitted an
emergency processing information collection request (ICR) to the Office
of Management and Budget (OMB) for review and clearance under the
Paperwork Reduction Act of 1995 (Pub. L. 104-13, 44 U.S.C. Chapter 35).
On August 17, OMB approved the request for clearance, assigning the
collection OMB Clearance No. 2127-0597. The emergency clearance will
expire on February 28, 1999. Through February 28, 1999, NHTSA is
authorized to collect 17,942 burden hours from the affected States, the
District of Columbia, and Puerto Rico.
National Environmental Policy Act
The agencies have reviewed this action for the purpose of
compliance with the National Environmental Policy Act (42 U.S.C. 4321
et seq.), and have determined that it will not have a significant
effect on the human environment.
Unfunded Mandates Reform Act
The Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires
agencies to prepare a written assessment of the costs, benefits and
other effects of proposed final rules that include a Federal mandate
likely to result in the expenditure by State, local or tribal
governments, in the aggregate, or by the private sector, of more than
$100 million annually. This interim final rule does not meet the
definition of a Federal mandate, because the resulting annual
expenditures will not exceed the $100 million threshold.
Interim Final Rule
This document is published as an interim final rule, without prior
notice and opportunity to comment. Because this regulation relates to a
grant program, the requirements of the Administrative Procedure Act
(APA), 5 U.S.C. 553, are not applicable. Moreover, even if the notice
and comment provisions of the APA did apply, the agency believes that
there is good cause for finding that providing notice and comment in
connection with this rulemaking action is impracticable, unnecessary,
and contrary to the public interest, since it would delay the
availability of guidance to States concerning new requirements
applicable during calendar year 1998. For the same reasons, we have
[[Page 46392]]
determined that notice and an opportunity for comment are not required
under the Department's regulatory policies and procedures.
States need this information immediately in order to comply with
requirements that are applicable to the observational seat belt surveys
they must conduct during the current calendar year. The statute
authorizing the grant program to which this interim final rule applies
(Pub. L. 105-178) was enacted on June 9, 1998, leaving little time for
States to both become familiar with new requirements that apply to
these surveys and conduct these surveys before the end of calendar year
1998. Moreover, for safety and practicability reasons, many States in
the northern latitudes must conduct surveys before the winter months,
leaving even less time for these States to meet the new requirements.
For these reasons, pursuant to 5 U.S.C. 808 (Pub. L. 104-121) (The
Congressional review provisions of the Small Business Regulatory
Enforcement Fairness Act), the agency also, for good cause, finds that
notice and public procedure are impracticable, unnecessary, and
contrary to the public interest, and, therefore, this rule can be made
effective upon publication.
As an interim final rule, this regulation is fully in effect and
binding upon its effective date. No further regulatory action by the
agency is necessary to make the rule effective. However, in order to
benefit from comments which interested parties and the public may have,
the agency is requesting that comments be submitted to the docket for
this rule. All comments submitted in response to this rule, in
accordance with the procedures outlined below, will be considered by
the agency. Following the close of the comment period, the agency will
publish a document responding to the comments and, if appropriate, the
agency will amend the provisions of this rule.
Comments
The agency is providing a 150-day comment period for interested
parties to present data, views, and arguments concerning this rule. The
agency invites comments on the issues raised in this notice and any
other issues relevant to this action. Comments must not exceed 15 pages
in length (49 CFR 553.21). This limitation is intended to encourage
commenters to detail their primary arguments in a concise fashion.
Necessary attachments may be appended to these submissions without
regard to the 15-page limit.
All comments received by the close of business on the comment
closing date indicated above will be considered and will be available
for examination in the docket at the above address both before and
after that date. To the extent possible, comments filed after the
closing date will also be considered. However, the rulemaking action
may proceed at any time after that date. Following the close of the
comment period, the agency will publish a document responding to the
comments and, if appropriate, the agency will amend the provisions of
this rule. The agency will continue to file relevant material in the
docket as it becomes available after the closing date, and it is
recommended that interested persons continue to examine the docket for
new material.
Those persons desiring to be notified of receipt of their comments
by the docket should enclose a self-addressed, stamped postcard in the
envelope with their comments. Upon receipt of the comments, the docket
supervisor will return the postcard by mail.
List of Subjects in 23 CFR Part 1340
Grant programs--transportation, Highway safety, Intergovernmental
relations, Reporting and recordkeeping requirements.
For the reasons set out in the preamble, title 23, chapter III of
the Code of Federal Regulations is amended as set forth below.
1. Part 1340 is added to read as follows:
PART 1340--UNIFORM CRITERIA FOR STATE OBSERVATIONAL SURVEYS OF SEAT
BELT USE
Sec.
1340.1 Purpose.
1340.2 Applicability.
1340.3 Basic design requirements.
1340.4 Population, demographic, and time/day requirements.
1340.5 Documentation requirements.
Appendix A to Part 1340--Sample Design
Authority: 23 U.S.C. 157; delegation of authority at 49 CFR
1.50.
Sec. 1340.1 Purpose.
This part establishes uniform criteria for surveys of seat belt use
conducted by States under 23 U.S.C. 157.
Sec. 1340.2 Applicability.
These uniform criteria apply to State surveys of seat belt use,
beginning in calendar year 1998 (except as otherwise provided in this
part), and continuing annually thereafter through calendar year 2001.
Sec. 1340.3 Basic design requirements.
Surveys conducted in accordance with this part shall incorporate
the following minimum design requirements:
(a) Probability-based requirement. The sample identified for the
survey shall have a probability-based design such that estimates are
representative of safety belt use for the population of interest in the
state and sampling errors may be calculated for each estimate produced.
(b) Observational requirement. Minimum requirements include the
following:
(1) The sample data shall be collected through direct observation
of seat belt use on roadways within the State, conducted completely
within the calendar year for which the seat belt use rate is being
reported;
(2) Seat belt use shall be determined by observation of the use or
non-use of a shoulder belt;
(3) Observers shall be required to follow a predetermined, clear
policy in the event that observations cannot be made at an assigned
site at the specified time (due to heavy rain, construction, safety
problems, etc.);
(4) Instructions to observers shall specify which road and which
direction of traffic on that road are to be observed (observers must
not be free to choose between roads at an intersection); and
(5) Observers shall follow clear instructions on how to start and
end an observation period and how to stop and start observations if
traffic flow is too heavy to observe all vehicles or if vehicles begin
moving too quickly for observation (to remove any possible bias, such
as starting with the next belted driver).
(c) Precision requirement. The relative error (standard error
divided by the estimate) for safety belt use must not exceed 5 percent.
Sec. 1340.4 Population, demographic, and time/day requirements.
Surveys conducted in accordance with this part shall comply with
the following minimum population, demographic, and time/day
requirements:
(a) Population of interest. (1) Drivers and front seat outboard
passengers in passenger motor vehicles (passenger cars, pickup trucks,
vans, and sport utility vehicles) must be observed in the survey. (Only
overall restraint use for the population of interest is required.
However, in order to assist in the evaluation of trends, it is
recommended that data be collected in such a way that restraint use
estimates can be reported separately for passenger cars and other
[[Page 46393]]
covered vehicles, and separately for drivers and front-seat outboard
passengers within those vehicle groups.)
(2) Surveys conducted during calendar year 1998 shall be deemed to
comply with paragraph (a)(1) of this section if passenger motor
vehicles registered in-State are included in the survey. For surveys
conducted during calendar year 1999 and thereafter, passenger motor
vehicles registered both in-state and out-of-state must be included in
the survey.
(b) Demographics. Counties, or other primary sampling units,
totaling at least 85 percent of the State's population must be eligible
for inclusion in the sample. States may eliminate their least populated
counties, or other primary sampling units, to a total of fifteen
percent or less of the total State population, from the sampling frame.
(c) Time of day and day of week. All daylight hours for all days of
the week must be eligible for inclusion in the sample. Observation
sites must be randomly assigned to the selected day-of-week/time-of-day
time slots. If cluster sampling is used, assignment of sites and times
within clusters must be random.
Sec. 1340.5 Documentation requirements.
All sample design, data collection, and estimation procedures used
in State surveys conducted in accordance with this part must be well
documented. At a minimum, the documentation must:
(a) For sample design--
(1) Define all sampling units, with their measures of size;
(2) Define what stratification was used at each stage of sampling
and what methods were used for allocation of the sample units to the
strata;
(3) Explain how the sample size at each stage was determined;
(4) List all samples units and their probabilities of selection;
and
(5) Describe how observation sites were assigned to observation
time periods.
(b) For data collection--
(1) Define an observation period;
(2) Define an observation site and what procedures were implemented
when the observation site was not accessible on the date assigned;
(3) Describe what vehicles were observed and what procedures were
implemented when traffic was too heavy to observe all vehicles; and
(4) Describe the data recording procedures.
(c) For estimation--
(1) Display the raw data and the weighted estimates;
(2) For each estimate, provide an estimate of one standard error
and an approximate 95 percent confidence interval; and
(3) Describe how estimates were calculated and how variances were
calculated.
Appendix A to Part 1340--Sample Design
Following is a description of a sample design that meets the
final survey guidelines and, based upon NHTSA's experience in
developing and reviewing such designs, is presented as a reasonably
accurate and practical design. Depending on the data available in a
State, substitutions in this design can be made without loss of
accuracy. This information is intended only as an example of a
complying survey design and to provide guidance for States
concerning recommended design options. These are not design
requirements. It is recommended that State surveys of safety belt
use be designed by qualified survey statisticians.
I. Sample Design
A. Sample population: It is recommended that all controlled
intersections or all roadway segments in the State (or in the parts
of the State that have not been excluded by the 85 present
demographic guideline) be eligible for sampling.
B. First Stage: Usually, counties are the best candidates for
primary sampling units (PSUs). In large States with differing
geographic areas, it is recommended that stratification of PSUs by
geographic region be employed prior to PSU selection. Counties
should be randomly selected, preferably with probabilities
proportional to vehicle miles of travel (VMT) in each county. If VMT
is not available by county, PSUs can also be selected with
probability proportional to county population. When sampling PSUs,
States should ensure that an adequate mix of rural and urban areas
are represented. In some cases, urban/rural stratification must be
employed prior to PSU selection. In other cases, it may be more
practical to perform urban/rural stratification at the second
sampling stage.
C. Second Stage: Within sampled PSUs, it is recommended that
road segments be stratified by road type. For example, a two-strata
design might be major roads vs. local roads, a three strata design
might be high, medium and low traffic volume roads. The sample
should be allocated to these strata by estimated annual VMT in each
stratum. The sample of road segments within a stratum should be
selected with probability proportional to average daily VMT. When
enumerating all local roads is impractical, additional stages of
selection can be introduced and alternative sample probabilities can
be used. For example, census tracts within counties can be selected
with probability proportional to VMT, or, if VMT is not available,
proportional to the square root of the population. Next, within each
sampled census tract, road segments can be selected.
D. Sample Size: The following tables are provided as rough
guidelines for determining sample size for estimating belt use with
the required level of precision. The numbers are based on results
from previous probability-based seat belt surveys.
Determining First Stage Sample Size
------------------------------------------------------------------------
Number
of
Number of counties in State counties
in
sample
------------------------------------------------------------------------
10............................................................ 7
20............................................................ 11
30............................................................ 13
40............................................................ 15
50............................................................ 16
60............................................................ 17
70............................................................ 18
80............................................................ 19
90............................................................ 19
100-120....................................................... 20
130-170....................................................... 21
More than 180................................................. 22
------------------------------------------------------------------------
Determining Second Stage Sample Size
------------------------------------------------------------------------
Number
of road
segments
Average number of road segments in each sampled county sampled
in each
sample
county
------------------------------------------------------------------------
50............................................................ 19
60............................................................ 20
70............................................................ 21
80............................................................ 21
90............................................................ 22
100........................................................... 23
200........................................................... 26
300........................................................... 27
400........................................................... 27
500-900....................................................... 28
More than 1000................................................ 29
------------------------------------------------------------------------
E. Example: To achieve the required level of precision, a State
with 100 counties would sample 20 counties at the first stage. At
the second stage, assuming an average of 100 road segments in each
sampled county, a sample of 23 road segments per county would be
selected. The total sample size would be 20 x 460 observational
sites.
II. Data Collection
A. Exact observation sites, such as the specific intersection on
a road segment, should be determined prior to conducting the
observations.
B. Direction of traffic to be observed should be determined
prior to conducting the observations.
C. If traffic volume is too heavy to accurately record
information, predetermined protocol should exist for selecting which
travel lanes to observe.
D. Observations should be conducted for a predetermined time
period, usually one hour. Time periods should be the same at each
site.
E. To minimize travel time and distance required to conduct the
observations, clustering of sampled sites can be done. Sample sites
should be grouped into
[[Page 46394]]
geographic clusters, with each cluster containing major and local
roads. Assignment of sites and times within clusters should be
random.
F. Two counts should be recorded for all eligible vehicles:
1. Number of front seat outboard occupants.
2. Number of these occupants wearing shoulder belts.
III. Estimation
A. Observations at each site should be weighted by the site's
final probability of selection.
B. An estimate of one standard error should be calculated for
the estimate of belt use. Using this estimate, 95 percent confidence
intervals for the estimate of safety belt use should be calculated.
Issued on: August 26, 1998.
Ricardo Martinez,
Administrator, National Highway Traffic Safety Administration.
[FR Doc. 98-23410 Filed 8-27-98; 11:54 am]
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