[Federal Register Volume 61, Number 109 (Wednesday, June 5, 1996)]
[Proposed Rules]
[Pages 28547-28550]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-14041]
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DEPARTMENT OF TRANSPORTATION
Federal Highway Administration
49 CFR Part 391
[FHWA Docket No. MC-96-4]
Proposed Research Plan on Vision Standard
AGENCY: Federal Highway Administration (FHWA), Department of
Transportation.
ACTION: Notice; request for comments.
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SUMMARY: The FHWA is requesting comments on a proposed research plan to
explore performance-based alternatives to the existing vision standard
for drivers of commercial motor vehicles (CMV). The findings of this
research effort may result in the modification of that standard. The
FHWA seeks comments on all aspects of the research plan, including its
scientific merit, likelihood of achieving its objective, methodological
validity, consideration of all relevant research, and other practical
issues.
The FHWA is also announcing a public hearing to obtain comments on
the proposed research plan. The hearing is designed to obtain public
input on the proposed research plan, not to determine the status of
individual drivers or participants in the vision waiver program. At the
hearing, the FHWA does not intend to discuss the status, results, or
recommendations that might result from the vision waiver program.
A review of scientific literature relevant to the vision standard
and the proposed research plan have been placed in FHWA Docket MC-96-4.
In addition, both documents are accessible electronically through the
Federal Highway Administration's World Wide Web (WWW) site.
DATES: The comment period will remain open until further notification
in the Federal Register. The public hearing will be held on August 9,
1996, at the Chicago O'Hare Marriot, 8535 West Higgins Road, Chicago,
IL, 60631, (312) 693-4444.
ADDRESSES: Submit written, signed comments to FHWA Docket MC-96-4, Room
4232, HCC-10, Office of the Chief Counsel, Federal Highway
Administration, 400 Seventh Street., SW., Washington, DC 20590.
The literature review and proposed research plan are on the Federal
Highway Administration's World Wide Web site (http://
cti1.volpe.dot.gov/ohim/whtnewhd). Users with questions about the
operation of the WWW site should call the FHWA Computer Help Desk at
(202) 366-1120.
FOR FURTHER INFORMATION CONTACT: Mr. Charles Rombro, Federal Highway
Administration, Office of Motor Carriers, 400 Seventh Street SW., room
3104, Washington, DC 20590, telephone (202) 366-5615. Office hours are
from 7:45 a.m. to 4:15 p.m., e.t., Monday through Friday, except
Federal holidays.
SUPPLEMENTARY INFORMATION: The FHWA is authorized by statute to
establish minimum physical qualification requirements for drivers of
commercial motor vehicles. 49 USC 31502.
The Congress provided the FHWA with complementary regulatory
authority with the enactment of the Motor Carrier Safety Act of 1984,
codified in substantial part at 49 U.S.C. 31101-31162. This Act
directed the Secretary to establish minimum safety standards to ensure,
inter alia, that ``the physical condition of operators of commercial
motor vehicles is adequate to enable them to operate such vehicles
safely * * *.'' 49 U.S.C. 31136(a)(3).
The physical qualification regulations for CMV drivers in
interstate commerce are found at 49 CFR 391.41. The qualification
standards cover 13 areas which directly relate to the driving function.
All but four of the standards adopted by the FHWA permit the individual
determination of a driver's qualification. A person's qualification to
drive is determined by a medical examiner who is knowledgeable about
the on-the-job functions performed by a commercial driver and whether a
particular condition would interfere with the driver's ability to
operate a CMV safely. In the case of vision, hearing, insulin-using
diabetes and epilepsy, the current standards are absolute, providing no
discretion to the medical examiner.
The current vision standard specifies that drivers must meet the
following three conditions:
1. distant visual acuity in each eye of at least 20/40, and distant
binocular acuity of at least 20/40 in both eyes; and
2. field of vision of at least 70 degrees in the horizontal
meridian of each eye; and
3. the ability to recognize the colors of traffic signals.
In order to improve protection for the public and provide for
individual determinations of fitness to drive wherever possible, the
Agency is interested in developing performance-based standards. In a
Federal Register notice on the vision waiver program published on
November 17, 1994 (59 FR 59386), the FHWA announced its intention to
initiate a research plan to ``develop parameters for performance-based
visual standards for all commercial drivers.'' 59 FR at 59389. The
research plan outlined in this notice is designed to move the Agency
towards a performance-based vision standard. This standard would
incorporate the measurement of those visual capabilities deemed
necessary for the safe operation of commercial vehicles. The research
discussed below is designed to relate specific visual functions to
specific driving tasks, such as the ability to stay in a lane. The
standards would still be prescriptive in that they would establish a
minimum score which individuals would be required to meet to be allowed
to drive; however, the scoring scheme would be based on detailed
research on the visual attributes required to safely operate a CMV.
Research Plan
The FHWA has developed a proposed research plan, an outline of
which is provided below.
Background
The FHWA's review of the existing literature on vision and driving
research led the FHWA to the following conclusions:
1. The current testing standard lacks criterion, or predictive,
validity; that is, it is not clear that central visual acuity by itself
is a good predictor of safe driving. This detracts from the perceived
fairness of the standard. The principal shortcoming of the current
standard is the emphasis on central visual acuity, which is a measure
of how well an individual can discern static images in the center of
vision under conditions of high luminance. Since many driving
situations involve dynamic images under low luminance, other visual
capacities may be equally
[[Page 28548]]
or more important than central visual acuity.
2. Improving the criterion validity of the vision standard would
most likely require testing a broader array of visual capabilities than
those included in the current standard.
3. There is no assurance that a standard based on a better
understanding of the relationship between different visual capabilities
and driving would result in a significant, measurable improvement in
safety, in part because vision is a contributor to only a small number
of crashes. CMV drivers comprise a small proportion of drivers, and are
represented in a small proportion of crashes, not all of which are
caused by failures of visual performance as currently measured.
However, the weak observed causal relationship between vision and
crashes may be a shortcoming with the current measurement of vision. It
is therefore possible that the measurement of other visual functions
could reveal a more significant and direct connection between vision
and driving ability.
The goals of the proposed research are threefold:
1. Establish a list of visual performance parameters that appear to
hold promise as a basis for a new standard, and design or adapt
performance tests to measure these capabilities.
2. Evaluate the predictive validity of these tests.
3. Based on the results of these tests, establish a trial vision
standard, and test that standard to evaluate its validity.
Outline of the Research Plan
The research contains both a long-term and a short-term track. The
Agency may decide to conduct either of the two tracks individually,
both tracks simultaneously, both tracks consecutively, or neither
track. The emphasis of the short-term plan is to build on existing
knowledge to develop an improved vision test, with the goal of adding
two or three existing vision tests to the battery currently tested.
This track does not call for significant new research, but rather seeks
to take advantage of already completed work. This track could result in
the development of a two-tier standard, with an expanded battery of
tests in the first (screening) tier, and various administrative
measures proposed for the drivers who do not pass this first tier.
Administrative measures may include provisional or restricted licenses,
waivers, or in-use monitoring of drivers.
The long-term plan consists of new research and analysis, which may
lead to the development of a new standard.
Two phases of the research are already complete. The short-term
research consists of six or seven additional stages, as explained
below. The long-term research would consist of four additional phases.
The phases of the research are described below.
Research Completed or Underway
1. Development of the research plan. This phase is complete, and
the work described below is the output of the planning effort. This
phase describes the proposed approaches in some detail; certain
elements are necessarily unspecified. For example, the choice of
specific visual function tests cannot be made before further research
and analysis are complete.
2. Design of testing strategy. This phase involves selecting and
developing the form of the candidate tests, as well as the measures
that the tests must predict. This phase is currently underway.
Selecting the candidate tests includes a general selection of
visual functions to be tested, an inventory of the tests already
available, and identification of new tests to be developed and
validated. Tests should have broad acceptance and stable underlying
population norms. The protocols for testing should be developed and
accepted by researchers and testers, and results must be stable
regardless of who administers the test. Acceptable population norms are
necessary if a test is to be used to classify individuals based on
``normal'' results in the population of CMV drivers.
While some tests, such as the Snellen Letter test of visual acuity,
are broadly accepted and have stable and well understood population
norms, other tests of potentially important visual functions do not
meet these standards. These latter tests would have to be evaluated.
The evaluation would consider how important the visual function is in
the driving task, the extent to which the test results are stable and
reliable, and how readily the tests can be developed for broad usage.
Our review of the literature has led us to focus on the following
visual functions as most relevant to the driving task: static acuity,
contrast sensitivity, dynamic acuity, working field of view, dark
focus, low contrast acuity, glare sensitivity, and vection.
The FHWA, with the assistance of a contractor, is in the process of
identifying the behaviors that the tests must predict--the measures of
effectiveness. This will be followed by the systematic development of
measures to be validated by the visual performance tests.
Theoretically, we would prefer to be able to relate a driver's
performance on vision tests to an actual driving record, especially the
driver's accident record. Because of the infrequency of accidents,
however, we would need to test a very large number of drivers over many
years to obtain reliable results. In addition, a ``clean'' experiment
would require that we allow drivers who we suspect may be deficient in
some key visual function to operate CMVs on the road. Allowing
potentially hazardous drivers to operate CMVs poses obvious safety
problems, and contravenes the FHWA's mandate to protect highway safety.
As a proxy for accidents, we are developing a list of candidate
visually- related driving behaviors. This is a reasonable proxy because
it is the driver's behavior that connects visual deficiencies and
accidents. An example might include the time a driver takes to initiate
a braking maneuver. Behaviors will be selected for further testing
based on their likely validity and practicality. Since we will not be
measuring accidents, it is especially important that the measures are
closely related to driving performance.
After choosing behavioral measures, the Agency will develop test
procedures and protocols.
Proposed Short-Term Research
3. Define criteria for selection of vision tests. The likely
criteria will include: test availability with little or no
modification, scientific reliability, construct validity, practicality
of use in a testing environment, and acceptability to researchers and
testers. While other criteria are possible, the FHWA anticipates that
the factors listed above will be used to screen tests for their
suitability for further research. Much of the work required to define
the criteria has already been completed under tasks 1 and 2.
4. Select candidate tests. The researchers would select 3 to 5
candidate tests for further research. The tests would have to meet the
criteria identified above. The researchers would determine which tests
meet these criteria through a survey of the scientific community and
other interest groups, and through the literature review conducted in
task 1.
5. Design demonstration/evaluation project. This task consists of
specifying the details of the testing procedures. The researchers would
select a site for the tests, choose criteria for obtaining
[[Page 28549]]
test subjects, and detail the protocols for administering the vision
tests.
6. Conduct empirical evaluation of operational feasibility. This is
the actual testing component, in which the drivers will be tested in an
operational setting to ensure that the new test battery's facilities
requirements are not excessive, its personnel needs are realistic, and
that the tests can be administered, scored, and interpreted in a timely
fashion by the individuals responsible for administering the tests.
7. Conduct empirical evaluation of validity of pass/fail criteria
for those candidate vision tests without sufficiently demonstrated
construct validity. The first step in this task would be to define the
study sample. The most likely sample would be age-matched 'visually
impaired' and 'visually unimpaired' subjects on the candidate tests
(all subjects would be required to hold a valid CDL). The researchers
would then conduct the vision and performance tests and analyze the
differences in performance between the two groups. Differences would be
measured relative to alternative cutoff scores, so that the Agency
could determine the significance of choosing different levels of
stringency.
The FHWA could decide to bypass task 7, the empirical validation
phase, if it determines that enough information currently exists to
establish a new standard, or that additional research would be unlikely
to lead to significant safety improvements. The Agency estimates that
skipping task 7 would reduce the time needed to complete the research
by one year.
8. Recommend tests and pass/fail criteria. Based on the work
completed above, the researchers would propose specific tests to be
added to the existing testing battery and cutoff scores for each test.
9. Convene interest groups to develop operational recommendations.
These groups would include motor vehicle licensing administrators,
researchers, industry associations, and safety advocates.
Proposed Long-Term Research
10. Design of tests and protocols. This includes developing the
visual performance and behavioral tests specified in task 2, generating
initial data from a pilot test, and designing draft protocols to be
used in later stages.
The visual function test would include some combination of existing
and new tests. The Agency would arrange the practical testing aspects,
including the purchasing and licensing of tests, acquiring any software
and documentation required, and developing the test protocols.
Pilot tests would be conducted on a small sample of drivers to
verify test reliability and suitability for large scale testing. The
Agency would modify procedures and protocols as appropriate. Upon
completion of the pilot test, the FHWA would conduct the visual
function tests on a medium-sized sample of drivers. The sample would be
large enough to allow the Agency to analyze test score characteristics.
Use of pilot tests would allow the Agency to ensure that a test would
produce useable results. In addition, correlation between tests may be
observed, in which case some tests may be eliminated from the final
battery as redundant.
For driver behavior measures, the agency would develop simulator
materials and closed-course testing procedures. To the extent possible,
the FHWA would employ procedures which can be used on multimedia
personal computers with a minimum of special equipment. The Agency
would develop hardware, software, and testing protocols.
The extent of the work performed in this task will depend on
whether the Agency conducts the short-term research. Some of the work
outlined above may be conducted in task 2 of the short-term track. If
that is the case, we will not repeat the work in this task.
11. Laboratory Simulation. This phase consists of evaluating the
candidate tests in a controlled setting, to identify and correct any
problems in the testing or protocols. This step is essentially a
``dress rehearsal'' for the full scale test. Because the next phase is
the most costly in terms of time and resources, this phase was designed
to allow the Agency to make a final decision about whether to continue
with the research prior to commencing with the next phase of the plan,
the full testing and evaluation.
A limited number of subjects would be given all the proposed visual
function and driver behavior tests. The results of these tests would be
analyzed extensively, including relationships between and among both
sets of tests. The analysis would address the following issues:
a. Are the distributions of scores useable?
b. Is there sufficient variance to discern relationships between
visual and driving tests?
c. How well do visual tests predict driving results, by themselves
and in combination with other tests? How much of the variance between
individuals in driving behavior can the vision tests explain?
The agency would also conduct a preliminary cost-benefit analysis.
In addition to projecting the cost of the next phases of the research
program, the analysis would estimate the cost of implementing a new
vision standard and the possible safety benefits.
12. Validation Testing. This phase consists of two sequential
activities, test preparation and data collection, the crux of the
proposed research.
Test preparation includes selection and configuration of test
sites, plus selection and preparation of subjects. The site (or sites)
selected must have, or be able to accommodate, a driving simulator, a
closed test course, and a road test course. Site preparation includes
configuring the testing equipment for the site, surveying the road test
course, and preparing and deploying signs and obstacles for the closed
test course. Preparation of the subjects consists of briefing the
participants and pre-testing them for the visual measures.
A final closed-course pilot test would then be conducted, using a
small number of drivers. This would provide the Agency with a final
opportunity to modify the test procedures.
Validation testing would probably include at least two distinct
activities, simulation and closed-course testing, and would possibly
also include controlled road testing. Variables would be strictly
controlled in these simulation tests to ensure the accuracy and
reliability of results. The FHWA expects that the simulators used for
this phase would be more sophisticated, with higher video resolution
than those used in the previous pilot test.
Closed-course testing would be used to test drivers under low
visibility conditions. This is difficult to imitate on a simulator and
is unsafe to test on the road.
If road testing is conducted, it would consist of non-intrusive
instruments to record driver responses, such as eye movement patterns,
blink rates, pupil diameter, and fixation points. This information,
combined with data on the roadway obstacles, provides a stream of data
related to working field of view, detection time, and how drivers react
to critical events. The road test would be conducted under normal
driving conditions to assure that the results are generalizable to
normal CMV operating practices. There are a number of hurdles to using
a road test, including the need to perform the test for an
impractically long period to obtain sufficient data, and the
possibility that drivers would modify their behavior if they are aware
[[Page 28550]]
that they are under observation. The FHWA would decide whether to
conduct the road test after analyzing the results obtained in the
simulation and closed-course tests.
13. Standard Development. The results of the preceding task would
be analyzed for validity, reliability, and practicality. If the results
of the validation testing justify specification of a new standard, a
decision framework for that standard would be constructed.
Specific Questions
The FHWA is specifically interested in comments addressing the
following issues:
1. Are there any methodological shortcomings in the research plan
outlined above that need to be addressed?
2. Is the plan likely to meet the objective of leading to an
improved, performance-based vision standard?
3. Does the plan reflect an understanding of the current literature
and consider its implications?
4. Is the plan capable of adequately addressing practical matters,
such as the cost of any new testing machinery developed, the level of
training required to conduct new tests, and the time needed to take
tests?
5. Has this type of research been conducted in other professions?
What were the results?
6. Should the FHWA proceed with the short-term plan, the long-term
plan, both, or neither?
7. Should the FHWA proceed with an alternative plan? If so,
describe that plan.
Current Status of the Research Program
The FHWA is currently in the midst of step 2 of the research plan,
which consists of inventorying existing tests and evaluating them
against a number of criteria, including their cost, which visual
functions they measure, overlap between different tests, and the amount
of training required to conduct the tests.
Format of Public Hearing
The FHWA announced in the November 17th notice (59 FR 59386) its
intention to hold a public hearing to discuss the research plan. The
public hearing will be held on August 9, 1996, at the Chicago O'Hare
Marriot, 8535 West Higgins Road, Chicago, IL 60631, (312) 693-4444. The
hearing will begin at 8:30 a.m. and conclude at 4:30 p.m.
Individuals wishing to speak at the hearing should contact the FHWA
at the address or phone number listed above under the heading ``For
Further Information Contact.'' Individuals may submit written comments
in addition to, or in place of, oral testimony. All commentors will be
limited to ten minutes of oral remarks.
The hearing will commence with an explanation of the proposed
research plan, including a brief description of the background to this
effort, the goals of the proposed research, and the steps of the
proposed plan. The FHWA will then accept questions from audience
members, with individuals who have contacted the FHWA given the first
opportunity to speak.
(49 U.S.C. 31136(a)(3), 31502)
Issued on: May 20, 1996.
Rodney E. Slater,
Federal Highway Administrator.
[FR Doc. 96-14041 Filed 6-4-96; 8:45 am]
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