Pub Ctzn v. FMCS

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United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued April 13, 2004 Decided July 16, 2004

No. 03-1165

PUBLIC CITIZEN, ET AL.,
PETITIONERS

v.

FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION,
RESPONDENT

DISTRIBUTION LTL CARRIERS ASSOCIATION, INC., ET AL.,
INTERVENORS

On Petition for Review of an Order of the
United States Department of Transportation

Bonnie I. Robin–Vergeer argued the cause for petitioners.
With her on the briefs were Brian Wolfman, Scott L. Nelson,
and Allison M. Zieve. Alan B. Morrison entered an appear-
ance.

Bills of costs must be filed within 14 days after entry of judgment.
The court looks with disfavor upon motions to file bills of costs out
of time.
 2

Henry M. Jasny was on the brief for amicus curiae
Advocates for Highway and Auto Safety in support of peti-
tioners.
Stephen L. Oesch, Shari T. Kendall, and Michele McDowell
Fields were on the brief for amicus curiae Insurance Insti-
tute for Highway Safety in support of petitioners.
Matthew M. Collette, Attorney, U.S. Department of Justice,
argued the cause for respondent. With him on the brief were
Peter D. Keisler, Assistant Attorney General, Robert S.
Greenspan and Tara Leigh Grove, Attorneys, Jeffrey A.
Rosen, General Counsel, U.S. Department of Transportation,
Paul M. Geier, Assistant General Counsel, Peter J. Plocki,
Senior Trial Attorney, and Brigham A. McCown, Chief Coun-
sel, Federal Motor Carrier Safety Administration.
Robert Digges, Jr. argued the cause for intervenors Ameri-
can Trucking Associations, Inc., et al. With him on the brief
were Erika Z. Jones, Adam C. Sloane, and David M. Gossett.
Robert A. Hirsch and Kevin M. Williams entered appear-
ances.
Before: EDWARDS, SENTELLE and TATEL, Circuit Judges.
Opinion for the Court filed by Circuit Judge SENTELLE.
SENTELLE, Circuit Judge: Public Citizen and other ‘‘public
interest’’ groups (collectively ‘‘Public Citizen’’ or ‘‘petitioners’’)
seek review of a final rule of the Federal Motor Carrier
Safety Administration (‘‘FMCSA’’ or ‘‘the agency’’) revising
existing hours of service (‘‘HOS’’) regulations limiting the
hours of driving and work of commercial motor vehicle opera-
tors. For the reasons more fully set out below, we agree
with petitioners that the rulemaking was arbitrary and capri-
cious, because the FMCSA failed to take account of a statuto-
ry limit on its authority. We therefore grant the petition for
review and vacate the rule.

I.
A. Regulatory Background
For years, federal regulators have limited the hours of
service that truckers, as well as other operators of various
 3

vehicles in the transportation industry, can work and operate
their motorized conveyances. The FMCSA, created by stat-
ute in 1999, is the agency charged with promulgating HOS
rules regulating drivers of commercial motor vehicles. When
Congress created the FMCSA, it provided as follows:
In carrying out its duties, the [FMCSA] shall consider
the assignment and maintenance of safety as its highest
priority, recognizing the clear intent, encouragement, and
dedication of Congress to the furtherance of the highest
degree of safety in motor carrier transportation.
42 U.S.C. § 113. Before Congress created the FMCSA, the
Federal Highway Administration (‘‘FHA’’) was responsible
for such rules.
In 1995, Congress ordered the FHA to revise the existing
commercial motor vehicle HOS rules. Specifically, it provid-
ed that the FHA
shall issue an advance notice of proposed rulemaking
dealing with a variety of fatigue-related issues pertaining
to commercial motor vehicle safety (including 8 hours of
continuous sleep after 10 hours of driving, loading, and
unloading operations, automated and tamper-proof re-
cording devices, rest and recovery cycles, fatigue and
stress in longer combination vehicles, fitness for duty,
and other appropriate regulatory and enforcement coun-
termeasures for reducing fatigue-related incidents and
increasing driver alertness).
49 U.S.C. § 31136 note. The FHA never issued the required
notice of rulemaking, and so it fell to the FMCSA to do the
job.
In May 2000, the FMCSA, in a formal notice published in
the Federal Register, proposed a new set of commercial
motor vehicle HOS rules. 65 Fed. Reg. 25,540 (2000) (‘‘NPR’’).
Though the rules regulate all cargo-carrying commercial mo-
tor vehicles, the petition before us addresses the impact of
the rule on long-haul truck drivers. The FMCSA promulgat-
ed those rules pursuant to, among other statutes, 49 U.S.C.
§ 31136 and § 31506, which are part of the Motor Carrier Act
 4

of 1935 and the Motor Carrier Safety Act of 1984. Section
31136 provides, in relevant part:
(a) Minimum safety standards TTT At a minimum, the
[HOS] regulations shall ensure that—
(1) commercial motor vehicles are maintained,
equipped, loaded, and operated safely;
(2) the responsibilities imposed on operators of com-
mercial motor vehicles do not impair their ability to
operate the vehicles safely;
(3) the physical condition of operators of commercial
motor vehicles is adequate to enable them to operate the
vehicles safely; and
(4) the operation of commercial motor vehicles does
not have a deleterious effect on the physical condition of
the operators.
Section 31506(d) provides:
Before prescribing or revising any [HOS] requirement,
[the FMCSA] shall consider the costs and benefits of the
requirement.
The NPR proposed to revise the existing HOS commercial
motor vehicle regulations, which had been in place (with some
revisions) since 1962. The old rules had placed limits on the
number of hours truckers could drive daily without off-duty
time, and the number of hours truckers could work weekly
during seven or eight consecutive days and still drive, with
some exceptions not relevant here. See 49 C.F.R. § 395.3
(2002) (superseded). These were limits on the time drivers
could work and still drive; so far as the rules went, drivers
who worked more than the daily or weekly limits could still
work as long as they did not drive. The daily limits prohibit-
ed truckers from driving more than ten hours without taking
eight hours of off-duty time or from driving after fifteen
hours ‘‘on duty’’ without taking eight hours of off-duty time.
Id. § 395.3(a)(1), (2). Drivers, however, could take periodic
‘‘off-duty’’ breaks during the day, thus extending the fifteen-
hour driving-eligible ‘‘on duty’’ period beyond fifteen hours.
The rules also permitted drivers to obtain the necessary eight
 5

nominally ‘‘consecutive’’ hours’ sleep by resting in a ‘‘sleeper
berth,’’ an enclosed compartment in the cargo space of a
truck with space for drivers to sleep. Drivers could obtain
their rest in sleeper berths in two separate periods totaling
eight hours, each of which was at least two hours long. Id.
§ 395.1(g). That meant that a long-haul truck driver could
satisfy regulatory requirements, for example, by driving six
hours, resting for five in his attached sleeper-berth, driving
another four, and resting another three hours. (The parties
refer to this feature of the old rules as the ‘‘sleeper-berth
exception.’’) The weekly driving limits prohibited driving
after having been on duty for sixty hours in seven consecutive
days, or seventy hours in eight consecutive days. Id.
§ 395.3(b). To enforce these requirements, the old rules
required drivers to maintain log books recording their hours
and duty status, and subjected drivers to roadside inspections
of the books. Id. § 395.8.
B. The Proposed Rule
The FMCSA proposed a significant revision to these rules
in the 2000 NPR. It based these revisions on some general
scientific conclusions regarding the consequences of sleep
deprivation among commercial motor vehicle operators. It
noted that research showed that people are much more alert
and have better reaction times when they are on regular,
twenty-four-hour circadian schedules, as humans are ‘‘pro-
grammed’’ to function best when they go to sleep and wake
up around the same time every day. 65 Fed. Reg. at 25,553–
54. These effects place nighttime drivers in a physiologically
vulnerable position, the agency concluded, because they must
sleep during the day, when their bodies are least receptive to
sleep, and work during the night, when they are physiologi-
cally and cognitively least able. That vulnerability of drivers,
in turn, creates a substantial risk of substandard and poten-
tially unsafe driving performance on the part of drivers unless
they obtain regular and sufficient restorative sleep. Id. at
25,554. To avoid these problems, the agency concluded that
drivers should get, at a minimum, ‘‘eight consecutive hours of
uninterrupted sleep every day.’’ Id.
 6

Accordingly, the agency proposed several revisions to the
existing HOS commercial motor vehicle driver regulations.
For long-haul truckers, the agency proposed to limit daily on-
duty and driving time to twelve hours, with two additional
hours off sometime during the workday, providing for a
maximum workday of fourteen hours. Id. at 25,581. (Sepa-
rate rules applied to other categories of commercial motor
vehicle drivers.) The NPR proposed requiring drivers to get
ten consecutive hours of off-duty time after a fourteen-hour
workday, putting drivers on a twenty-four-hour cycle, assum-
ing they maximized work time and minimized off-duty time.
Id.
There were at least three justifications for the increase in
mandatory off-duty time and the decrease in permissible on-
duty time. The first was the need to increase the old rules’
eighteen-hour on-duty/off-duty work cycle to a twenty-four
hour cycle; the old rules had permitted an eighteen-hour
cycle by requiring only eight hours of off-duty time after ten
hours of driving. The change to a twenty-four hour maxi-
mum cycle, the agency reasoned, better approximated circadi-
an rhythms. The second was the need to allow enough time
for drivers to get sufficient continuous sleep. The old rules,
by requiring only eight hours of off-duty time, concluded the
agency, had not allowed drivers to obtain seven or eight
hours’ sleep, because drivers had to spend much of this off-
duty time on daily personal tasks, such as commuting, eating
meals, running personal errands, and having a family and
social life. Id. at 25,554. The last justification was the
agency’s conclusion that the risk of a driver crashing ‘‘in-
creases markedly after the 12th hour of any duty time during
the work shift,’’ which justified limiting daily on-duty and
driving time to twelve hours. Id. at 25,556.
The agency also proposed to modify the old rules’ sleeper-
berth exception. Citing research showing that split-sleep was
less restorative than continuous sleep, the agency proposed to
eliminate the exception for solo drivers. Id. at 25,586. That
would mean that solo drivers could no longer accumulate the
required amount of off-duty time by splitting their time in a
sleeper berth. The agency proposed to retain the exception
 7

for team drivers, but increased the minimum sleeper-berth
period from two to five hours. Id. at 25,587. The proposal,
in addition, no longer allowed drivers to extend their ‘‘on-
duty’’ period by taking periodic breaks during the day and
instead provided for a mandatory off-duty period of two
hours. It counted any additional break time against drivers’
total on-duty driving-eligible time.
The rule proffered in the NPR also would have required
drivers to take a mandatory ‘‘weekend’’ of thirty-two to fifty-
six hours off-duty each week, covering two consecutive peri-
ods from 12 a.m. to 6 a.m. Id. at 25,581, 25,568 tbl. 5, 25,587–
88. This additional recovery period was necessary, according
to the agency, to compensate for sleep debts drivers accrue
during each weeks’ work. Id. at 25,555–56. In addition, the
weekend would ensure that drivers have an opportunity to
sleep during two nighttime periods each week – ‘‘circadian-
optimal times’’ – and prevent drivers from having to work five
consecutive night shifts. Id. at 25,557–58.
Finally, the proposed rule would have required truckers to
use electronic onboard recorders (‘‘EOBRs’’) instead of log-
books to monitor their adherence to the new regulatory
requirements. Id. at 25,598. Those recorders would auto-
matically monitor the date, driving distance per day, on- and
off-duty time, start time, and would have a continuous time
scale. See id. at 25,606. Drivers would not be permitted to
edit the recorded figures. The agency proposed requiring
such recorders because it determined that falsification of
logbooks, the only form of compliance monitoring mandated
by the old rules, was widespread. Id. at 25,558.
C. The Final Rule
The eventual rule, promulgated in April 2003, was still a
significant revision to the old rules, but differed markedly
from the NPR. See 68 Fed. Reg. 22,456 (2003). The new
rule prohibited truckers from driving without ten hours of off-
duty time after fourteen hours of starting work and limited
daily driving time during that work period to eleven hours.
Id. at 22,457. As compared to the old rules, those limits
increased the required off-duty time from eight to ten hours,
 8

decreased the total permissible driving-eligible workday from
fifteen to fourteen hours, but increased the total maximum
daily possible driving from ten to eleven hours. The new
rules also eliminated a loophole in the old rules. As dis-
cussed, the old rules had allowed drivers to extend the
fifteen-hour duty period by taking breaks throughout the day,
allowing them to drive after having been at work much more
than fifteen hours. By prohibiting driving fourteen hours
after starting work, rather than after fourteen hours ‘‘on
duty,’’ the new rules eliminated this loophole and prohibited
driving after fourteen hours of work, including on-duty
breaks. Unlike the rule proposed in the NPR, however, the
final rule did not require a mandatory two-hour break during
the day.
This regulatory framework set drivers’ schedules at a
twenty-one-hour daily cycle for those who drove the maxi-
mum number of hours (eleven) and then took the minimum
possible number of off-duty hours (ten). Drivers who
worked – both by driving and other tasks – the maximum
possible on-duty driving-eligible time (fourteen hours), howev-
er, had a twenty-four-hour daily cycle if they maximized
working hours and minimized off-duty time (ten hours). Fol-
lowing the research cited in the NPR, the agency recognized
a ‘‘general agreement on the concept of a 24–hour work/rest
cycle,’’ i.e., the body’s natural circadian rhythms. Id. at
22,469. The agency, however, justified not requiring all
drivers to operate on a twenty-four-hour cycle by saying that
such a rule would unduly disrupt the trucking industry,
though it conceded that such a rule would be ‘‘ideal from a
scientific viewpoint.’’ Id. Still, the agency noted that its
framework ‘‘move[d] toward a 24–hour work/rest cycle’’ while
minimizing the costs of making the rule ‘‘inflexible.’’ Id.
The agency also considered, and rejected, the NPR’s pro-
posed mandatory ‘‘weekend’’ at the end of each work week,
although it retained the old rules’ prohibition of driving after
more than sixty hours of on-duty time during a seven-day
period, and after more than seventy hours of on-duty time
during an eight-day period. Id. at 22,502. The mandatory
weekend requirement, the agency implied, ‘‘would create
 9

havoc on the already overcrowded highways in the daylight
hours,’’ by restricting nighttime driving. Id. at 22,477. In-
stead of a mandatory weekend, the agency allowed a thirty-
four-hour ‘‘restart’’ provision. Id. at 22,502. This provision
permitted drivers to ‘‘restart’’ their work week after taking
thirty-four consecutive hours off-duty, meaning that they
could work a new seven- or eight-day consecutive driving
period that comported with the weekly maximum hour limits.
The agency justified the restart provision by arguing that
thirty-four hours was enough to allow drivers to obtain seven
or eight hours of uninterrupted sleep on each of two consecu-
tive days, thereby allowing them to obtain adequate restora-
tive sleep and freeing them to start driving anew as part of a
sixty- or seventy-hour work week. Id. at 22,479.
As compared to the old rules, the restart provision in-
creased the number of hours truckers could work per week.
The old rules had capped the number of hours a trucker could
drive after working each week at sixty (or seventy for eight
days) regardless of whether a trucker got thirty-four hours’
consecutive rest during the week. The new rules, by con-
trast, allowed drivers to work more hours if they took thirty-
four hours off before the close of the weekly limits. A driver
could work seventy-seven hours over seven days, for example,
by working twenty-one hour-driving/rest rotations seven days
a week, assuming the driver took thirty-four consecutive
hours off after driving the maximum fifty-five hours and took
the minimum forty hours off over the first four calendar days.
The final rule also revised the NPR’s proposed restructur-
ing of the sleeper-berth exception. The NPR had proposed
eliminating that exception for solo drivers but retaining it, in
modified form, for team drivers. The agency ultimately
decided that this was unwise. It decided to allow drivers to
obtain the required ten hours’ rest in exactly two chunks, one
of which was at least two hours long (in contrast to the five-
hour minimum the NPR’s recommendation would have re-
quired for team drivers). 49 C.F.R. § 395.1(g) (2003). The
NPR’s rule would have instead required that solo drivers take
ten continuous hours off duty, whether spent in a sleeper
berth or not.
 10

In retaining the sleeper-berth exception for solo drivers,
the agency reasoned that the ‘‘proximity and convenience’’ of
the berths for truckers reduced the importance of having a
longer rest period for drivers who sleep in berths. 68 Fed.
Reg. at 22,466. A longer period, the agency worried, would
be unduly inflexible, as it would require a driver who sleeps
for seven hours in a berth to refrain from working another
three hours. Id. The final rule noted, too, that ninety
percent of truckers currently use sleeper berths, and that
their use ‘‘is firmly entrenched in the practice, culture, and
equipment of the trucking industry.’’ Id. The agency also
cited a lack of evidence that retaining the sleeper-berth
exception was a safety hazard, and concluded that the exist-
ing studies that purported to show that dividing sleep in
berths was dangerous were actually inconclusive. Id. at
22,465–66.
The agency altered the proposed rule on yet another point.
The NPR had proposed requiring truckers to install EOBRs
to monitor compliance with the rules; in the final rule the
FMCSA decided not to do so ‘‘at this time,’’ but instead to
continue relying on logbooks. Id. at 22,488. The agency
reasoned that there was insufficient evidence regarding the
costs and benefits of requiring EOBRs. Id. The agency also
was concerned that it would be difficult to standardize
EOBRs and that they would be expensive. Id. Finally, the
agency cited concerns that the recorders would be unduly
intrusive. Id.
This petition for review followed.

II.
Petitioners claim that the final rule is arbitrary and capri-
cious in several respects. We review the adequacy of the
agency’s reasoning under the familiar standard of Motor
Vehicle Manufacturers Association v. State Farm Mutual
Life Insurance Co., 463 U.S. 29, 41–44 (1983). That requires
us to ensure that the agency made a ‘‘rational connection
between the facts found and the choice made.’’ Id. at 43
(internal quotation marks and citation omitted). We agree
with petitioners that the rule is arbitrary and capricious
 11

because the agency failed to consider the impact of the rules
on the health of drivers, a factor the agency must consider
under its organic statute. Because the agency has wholly
failed to comply with this specific statutory requirement, this
single objection from petitioners is sufficient to establish an
arbitrary-and-capricious decision requiring vacatur of the
rule.
Several of petitioners’ other objections also raise troubling
concerns about the decisionmaking process. We do not,
however, enter final judgment on those, as we are vacating
and remanding the matter in any case and the agency will be
free in its further proceedings to consider the other objec-
tions anew in light of this opinion and its own responses to
the driver health requirement.
A. Driver Health
We hold that the final rule is arbitrary and capricious
because the agency neglected to consider a statutorily man-
dated factor – the impact of the rule on the health of drivers.
In promulgating ‘‘regulations on commercial motor vehicle
safety,’’ and HOS regulations are undoubtedly on that exact
subject, the FMCSA is required ‘‘[a]t a minimum [to] ensure
that TTT the operation of commercial motor vehicles does not
have a deleterious effect on the physical condition of the
operators.’’ 49 U.S.C. § 31136(a)(4). As the Supreme Court
stated in State Farm, an agency’s rule normally is arbitrary
and capricious if it ‘‘entirely failed to consider an important
aspect of the problem’’ before it. 436 U.S. at 43. A statutori-
ly mandated factor, by definition, is an important aspect of
any issue before an administrative agency, as it is for Con-
gress in the first instance to define the appropriate scope of
an agency’s mission. When Congress says a factor is manda-
tory, that expresses its judgment that such a factor is impor-
tant. In accordance with this principle, we have held that
‘‘the complete absen[c]e of any discussion’’ of a statutorily
mandated factor ‘‘leaves us with no alternative but to con-
clude that [the agency] failed to take account of this statutory
limit on [its] authority,’’ making the agency’s reasoning arbi-
 12

trary and capricious. United Mine Workers v. Dole, 870 F.2d
662, 673 (D.C. Cir. 1989).
The FMCSA points to nothing in the agency’s extensive
deliberations establishing that it considered the statutorily
mandated factor of drivers’ health in the slightest. Instead,
the agency states that ‘‘[t]he statute does not require the
agency to protect driver health to the exclusion of other
considerations such as the costs and benefits of the proposed
regulation.’’ FMCSA Br. at 54–55. But neither petitioners
nor the court suggests that the statute requires the agency to
protect driver health to the exclusion of those factors, only
that the agency must consider it. So far as the record
reveals, it did not.
The FMCSA’s only effort to show that it did consider
driver health is to point out that it considered the effect of
driver health on vehicle safety and to argue that consideration
of the health of drivers therefore ‘‘permeated the entire
rulemaking process.’’ FMCSA Br. at 55. But the statute
requires the agency to consider the impact of the rule on ‘‘the
physical condition of the operators,’’ not simply the impact of
driver health on commercial motor vehicle safety. 49 U.S.C.
§ 31136(a)(4). Under the statute, vehicle safety is a distinct
factor the agency must consider, so considering the effect of
driver health on safety cannot be equal to considering the
impact on the physical condition of the operators. Id.
§ 31136(a)(2), (3). It is one thing to consider whether an
overworked driver is likely to drive less safely and therefore
cause accidents. Whether overwork and sleep deprivation
have deleterious effects on the physical health of the driver is
quite another. This is not to suggest that the two factors are
unrelated: healthy drivers presumably cause fewer accidents
and conversely drivers who have fewer accidents suffer fewer
injuries. However, the relatedness of the concept discussed
to the statutorily mandated factor that the agency does not
discuss does not relieve the agency of the duty of compliance
with the congressional instruction.
It may be the case, for example, that driving for extended
periods of time and sleep deprivation cause drivers long-term
 13

back problems, or harm drivers’ immune systems. The agen-
cy may of course think that these and other effects on drivers
are not problematic (or are outweighed by other consider-
ations, like cost), but if so it was incumbent on it to say so in
the rule and to explain why. Its failure to do so, standing
alone, requires us to vacate the entire rule as arbitrary and
capricious, as the agency’s failure to consider this factor, to
borrow a phrase from the agency’s brief, ‘‘permeated the
entire rulemaking process.’’
B. Other Concerns with the Rule
As we said above, we will not render final decision on
petitioners’ other objections to the rule, as the failure of the
agency to consider the statutorily mandated factor is disposi-
tive and especially because the agency’s handling of the other
factors may be different after reconsideration in light of
whatever decisions it may reach with respect to the effect of
the rule on driver health on remand. We nonetheless note,
for a sense of completeness, the troubling nature of these
other facets of the rulemaking.
1. Increase in Maximum Driving Time from Ten to
Eleven Hours
Petitioners challenge the rationality of the agency’s deci-
sion to increase the maximum permissible daily driving time
from ten to eleven hours. This challenge illustrates the
relatedness of the entire rulemaking to the statutorily man-
dated driver-health factor upon which we are turning our
decision. While the challenge to the increase in driving time
is distinct, and theoretically could be the basis of the granting
of a petition for review by itself, it is also a factor that the
agency may wish to consider anew in weighing the effects of
the rulemaking on the physical condition of drivers.
In any event, petitioners’ challenge raises very real con-
cerns. The old HOS regulations, as we have discussed, had
prohibited truckers from driving more than ten hours without
taking eight hours off during the day and had limited truck-
ers’ driving-eligible time to fifteen hours ‘‘on duty’’ without
taking eight hours of off-duty time. While the final rule
 14

increased the minimum amount of off-duty time from eight to
ten hours, and decreased permissible driving-eligible on-duty
time from fifteen to fourteen hours, it increased the maximum
permissible daily driving time from ten to eleven hours.
The agency had essentially two justifications for increasing
maximum daily driving time. It said that the increase was
justified by the decrease in overall daily driving-eligible ‘‘tour
of duty’’ from fifteen to fourteen hours. 68 Fed. Reg. at
22,473. It also said that the increase in mandatory off-duty
time from eight to ten hours justified the increase in daily
driving time in light of the cost-benefit analysis it had con-
ducted. Id. at 22,471.
We have our doubts about whether these two justifications
are legally sufficient. The agency freely concedes that ‘‘stud-
ies show[ ] that performance begins to degrade after the 8th
hour on duty and increases geometrically during the 10th and
11th hours’’ on duty. Id. Despite this finding, the agency
cited absolutely no studies in support of its notion that the
decrease in daily driving-eligible tour of duty from fifteen to
fourteen hours will compensate for these conceded and docu-
mented ill effects from the increase.
The agency did refer generally to studies, but that general-
ized reference is of doubtful legal sufficiency. The agency in
particular stated that it ‘‘relie[d] upon 12 studies to select a 10
consecutive houroff-duty [sic] period, a 14–hour tour of duty,
and a maximum of 11 hours of driving’’ and noted that an
annotated literature review of those studies is in the rulemak-
ing docket. Id. at 22,473. But the agency never stated
which particular studies in fact justify the increase, much less
how they do so. Unlike the discussion in the rule, the
agency’s brief before this court does cite several studies with
particularity; but those citations cannot save the rule. The
expertise of the agency, not its lawyers, must be brought to
bear on this issue in the first instance. See SEC v. Chenery,
318 U.S. 80, 87–88 (1943).
Moreover, although the agency is correct that it decreased
the maximum daily driving-eligible on-duty time, the agency
also, as discussed above, increased the maximum weekly on-
 15

duty time for those drivers maximizing weekly driving time
and who take advantage of the thirty-four-hour restart provi-
sion. Even assuming that the agency had adequately docu-
mented the beneficial effects from the decreased daily driv-
ing-eligible ‘‘tour of duty,’’ the effects from the increased
weekly driving hours may offset any decrease in fatigue
flowing from the fact that drivers have shorter over-all tours
of duty. For these two reasons, it is unlikely that we would
find the agency’s first explanation legally sufficient.
The agency’s second justification is also dubious. That
explanation relies on the cost-benefit analysis it conducted.
The analysis purports to show that the benefits from the rule
outweigh its costs, given that the agency increased (as com-
pared to the old HOS regulations) mandatory daily off-duty
time from eight to ten hours. But this analysis assumes,
dubiously, that time spent driving is equally fatiguing as time
spent resting – that is, that a driver who drives for ten hours
has the same risk of crashing as a driver who has been
resting for ten hours, then begins to drive. 68 Fed. Reg. at
22,497. In other words, the model disregarded the effects of
‘‘time on task’’ because, the agency said, it did not have
sufficient data on the magnitude of such effects. Id.
This assumption makes the cost-benefit analysis of ques-
tionable value in justifying the increase in daily driving time.
The exponential increase in crash risk that comes with driv-
ing greater numbers of hours, presumably caused by time-on-
task effects, raises eyebrows about the agency’s increase of
daily driving time. Yet the agency excluded time-on-task
effects from the cost-benefit analysis. That analysis, then,
assumes away the exact effect that the agency attempted to
use it to justify. The agency’s reliance on the cost-benefit
analysis to justify this increase is therefore circular, and the
rationality of that explanation is correspondingly doubtful.
Quite apart from the circularity of the agency’s explanation,
moreover, the model’s assumption that time-on-task effects
are nil is implausible. Again, the agency admits that studies
show that crash risk increases, in the agency’s words, ‘‘geo-
metrically,’’ id. at 22,471, after the eighth hour on duty, and
 16

the agency does not deny that this geometric risk increase
results at least in substantial part from time-on-task effects.
The mere fact that the magnitude of time-on-task effects is
uncertain is no justification for disregarding the effect entire-
ly. The agency, for example, could have extrapolated the
time-on-task effects of driving longer hours using crash-risk
data derived from drivers who drove for shorter periods of
time. In light of this dubious assumption, the agency’s cost-
benefit analysis is questionable, and, as a consequence, so is
its justification for increasing maximum driving time from ten
to eleven hours.
2. Sleeper–Berth Exception
Our doubts extend as well to the agency’s justification for
retaining the sleeper-berth exception. The final rule, again,
permits solo and team drivers to obtain the necessary ten
hours of off-duty time by splitting their rest in two periods of
time spent in sleeper berths, at least one of which is two
hours long. 49 C.F.R. § 395.1(g) (2003). Petitioners argue
persuasively that the agency’s justification for retaining this
exception was not rational in view of the conceded central
premise of the HOS regulations, shared by the NPR and the
final rule, that ‘‘[e]ach driver should have an opportunity for
eight consecutive hours of uninterrupted sleep every day.’’
68 Fed. Reg. at 22,469.
Despite that premise, the agency offered several justifica-
tions for nevertheless permitting drivers to obtain the re-
quired continuous period of rest in two chunks, all of which
are quite weak. First, the agency cited two studies, Dingus
et al., Impact of Sleeper Berth Usage on Driver Fatigue
(2002); and Wylie et al., Commercial Motor Vehicle Driver
Fatigue and Alertness Study (1996). 68 Fed. Reg. at 22,465.
The agency cited the first study for the proposition that
‘‘[s]tudies on the sleeper berth issue have generally found
that, for a number of reasons, sleeping in a berth, particularly
when the vehicle is moving, is less restorative than sleeping in
a bed.’’ Id. at 22,464. The agency also noted that team
drivers used sleeper berths more effectively than solo drivers
did. Id. at 22,465.
 17

It is not clear how the Dingus study could rationally justify
retaining the sleeper-berth exception. The conclusions that
the agency draws from the study either do not support
retaining the exception or have nothing to do with the prob-
lem of sleeper-berth rest. For one, the agency’s citation to
the study for the idea that sleeping in a berth is less
restorative than sleeping in a bed supports eliminating, not
retaining, the exception. Similarly, the agency’s observation
that solo drivers less effectively use sleeper berths than do
team drivers also supports eliminating the exception for solo
drivers, as the rule proposed in the NPR would have. For
another, a study comparing the effects of sleeper berth usage
on team drivers and solo drivers says little about whether, as
an absolute matter, retaining the exception is safe. Congress
directed the FMCSA to ensure that ‘‘commercial motor vehi-
cles are TTT operated safely,’’ 49 U.S.C. § 31136(a)(1), not to
ensure that commercial motor vehicles driven by team drivers
are safe relative to those driven by solo drivers. The Dingus
study, in short, is weak justification for retaining the excep-
tion.
The agency’s use of the Wiley study is also difficult to
understand. The Wiley study did not even evaluate the
problem of sleeper-berth sleep, much less split sleeper-berth
sleep; the drivers in that study slept in hospitals and motels,
not sleeper berths. The Wiley study thus is also weak
evidence that retaining the sleeper-berth exception is appro-
priate.
The other justifications the agency used to justify the
sleeper-berth exception are also unimpressive. The agency
noted that ‘‘the proximity and convenience of the sleeper-
berth reduces the importance of the length of the uninter-
rupted period.’’ Id. at 22,466. That says nothing about
whether drivers should be able to split their rest in a sleeper
berth; at most, it would justify reducing the required length
of continuous rest if a driver spends the time in a berth,
which the rule does not do. The agency also said that ‘‘[u]se
of sleeper berths in long-haul operations is firmly entrenched
in the practice, culture, and equipment of the trucking indus-
try,’’ and that therefore to eliminate the sleeper-berth excep-
 18

tion ‘‘would require more documented evidence of a safety
problem than the agency now has.’’ Id. This is another
nonsequitur. Eliminating the sleeper-berth exception would
not prevent drivers from using sleeper berths. It would only
prevent them from splitting their rest in them.
In sum, we have grave doubts about whether the agency’s
explanation for retaining the sleeper-berth exception would
survive arbitrary-and-capricious review.
3. EOBRs
The agency’s justification for not requiring EOBRs to
monitor driver compliance is another aspect of the final HOS
rule of questionable rationality. Recall that the agency had,
in the NPR, proposed to require commercial motor vehicle
companies to use EOBRs to monitor driver compliance. The
final rule decided not to require EOBRs ‘‘at this time.’’ Id. at
22,488.
The agency gave three primary reasons for not doing so.
First, the agency said that ‘‘neither the costs nor the benefits
of EOBR systems are adequately known,’’ because there is no
‘‘significant market’’ for the devices, and because the amount
of HOS-noncompliance that EOBRs would detect is unknown,
as the agency ‘‘did not test the (very few) EOBRs currently
available.’’ Id. Second, the agency said that because the
NPR’s proposed EOBR requirement was drafted as a per-
formance, not a design, standard, enforcement officials ‘‘would
have to waste time and effort mastering incompatible read-
out procedures created by different EOBR vendors,’’ and that
the solution to this problem ‘‘at least for now, is to adopt a
rule that does not require EOBRs.’’ Id. Finally, the agency
stated that drivers see EOBRs as a ‘‘direct assault on their
dignity and privacy,’’ and that the information recorded in
EOBRs could be used in lawsuits against trucking companies.
Id. at 22,489.
This explanation is probably flawed. In section 408 of the
Interstate Commerce Commission Termination Act of 1995,
49 U.S.C. § 31136 note, Congress directed the FMCSA to
issue
an advance notice of proposed rulemaking dealing with a
variety of fatigue-related issues pertaining to commercial
 19

motor vehicle safety (including 8 hours of continuous
sleep after 10 hours of driving, loading, and unloading
operations, automated and tamper-proof recording de-
vices, rest and recovery cycles, fatigue and stress in
longer combination vehicles, fitness for duty, and other
appropriate regulatory and enforcement countermeas-
ures for reducing fatigue-related incidents and increasing
driver alertness).
(emphasis added). This directive, in our view, required the
agency, at a minimum, to collect and analyze data on the costs
and benefits of requiring EOBRs. ‘‘Deal[ ] with,’’ in the
sense meant here, means ‘‘to take action with regard to
someone or something.’’ Merriam Webster’s Collegiate Dic-
tionary 296 (10th ed. 1995). Because the agency is required
to ensure that ‘‘commercial motor vehicles are maintained,
equipped, loaded, and operated safely,’’ 49 U.S.C.
§ 31136(a)(1), and because the agency is also required to
‘‘consider the costs and benefits’’ of HOS regulations, id.
§ 31506(d), the ‘‘action’’ undoubtedly meant here means, at a
minimum, fulfilling the agency’s statutory duty to weigh the
costs and safety benefits of requiring EOBRs. (Although the
statutory requirement applies by its terms to ‘‘an advance
notice of proposed rulemaking,’’ we think the implication plain
that the final rule, necessarily derived from the NPR, is
subject to the same requirement.) True, as the agency points
out, this statutory provision does not require the agency to
promulgate a rule that requires the use of EOBRs; but it
does require the agency to evaluate seriously whether
EOBRs should be required.
The agency’s explanation in all likelihood does not conform
to this statutory requirement. The agency said that the costs
and benefits of EOBRs are unknown, because cost estimates
‘‘vary enormously.’’ But nothing prevented the agency from
itself estimating the costs. The agency’s job is to exercise its
expertise to make tough choices about which of the competing
estimates is most plausible, and to hazard a guess as to which
is correct, even if the lack of a ‘‘significant market for such
devices’’ means that the estimate will be imprecise. Regu-
lators by nature work under conditions of serious uncertainty,
 20

and regulation would be at an end if uncertainty alone were
an excuse to ignore a congressional command to ‘‘deal[ ] with’’
a particular regulatory issue.
A similar problem infects the agency’s discussion of the
benefits of EOBRs. The agency concedes that it ‘‘did not test
the (very few) EOBRs currently available.’’ The agency
offers no excuse for not doing so, and we can think of none
that would suffice to fulfill the agency’s duty to ‘‘deal[ ] with’’
the issue of EOBRs. Given the large incentives truckers
have to falsify their logbooks, incentives confirmed by the
agency’s recognition in the NPR that noncompliance with
HOS regulations is ‘‘widespread,’’1 65 Fed. Reg. at 25,567,
noncompliance with HOS regulations is no doubt a serious
regulatory problem, as the agency and its lawyers do not
deny. It stands to reason that requiring EOBRs will have
substantial benefits by inducing compliance with HOS regula-
tions, and the agency concedes that compliance with HOS
regulations has benefits. It is therefore facially plausible that
EOBRs will have substantial safety benefits, and it was
incumbent on the agency at least to attempt to analyze those
benefits.
We cannot fathom, therefore, why the agency has not even
taken the seemingly obvious step of testing existing EOBRs
on the road, or why the agency has not attempted to estimate
their benefits on imperfect empirical assumptions. (The
agency, as we have discussed, apparently had no problem
making estimates based on imperfect empirical assumptions
when it estimated the costs of increasing driving time from
ten to eleven hours.) The agency is no doubt correct that the
‘‘amount of cheating that could be deterred by EOBRs is
unknown,’’ id. at 22,488, but this lack of knowledge is willful,
1 Driver noncompliance with federal regulation in this and related

areas might be described as the stuff of legend. See, e.g., E. Green
and C. Montgomery, ‘‘Six Days on the Road’’:
The I.C.C. is a-checkin on down the line.
Well, I’m a little overweight and my log books are way behind.
But nothing bothers me tonight, I can dodge all the scales all
right,
Six days on the road, I’m gonna make it home tonight.
 21

given that the agency has not even attempted testing of the
existing units. As petitioners stress, the agency has provided
for voluntary use of EOBRs among truckers for over fifteen
years, see 49 C.F.R. § 395.15, so such testing is in all proba-
bility eminently possible. The agency has offered no good
reason for treating this problem with such passivity.
Without such a cost-benefit analysis, accounting for bene-
fits as well as costs, we do not understand how the remainder
of the agency’s explanation, all of which focuses solely on the
costs of the rule, could pass muster in this court on petition
for review. The second and third primary justifications for
not requiring EOBRs – that implementing a performance,
rather than a design, standard might be difficult, and that
EOBRs might be unduly intrusive – might well be outweighed
by the benefits of requiring EOBRs in the first place. We
and the agency, however, have no idea whether they would,
because the agency has not bothered to study what benefits
EOBRs might have. This one-sided and passive regulatory
approach in all likelihood does not comport with Congress’s
direction for the agency to ‘‘deal[ ] with’’ this issue in light of
the statutorily mandated factors for which it has provided.
4. Thirty–Four–Hour Restart
One further problematic aspect of the agency’s explanation
for the rule concerns the thirty-four-hour restart provision.
As discussed, this provision has the effect of increasing the
maximum number of hours drivers can work each week. The
agency justified the restart on the ground that after having
thirty-four hours of rest, drivers have the opportunity to get
seven-to-eight hours of continuous rest, and because the
restart will help drivers keep a regular schedule. 68 Fed.
Reg. at 22,479. For example, if a driver gets off work at 8
p.m. Saturday after starting work that day at 6 a.m. (a
fourteen-hour day), the thirty-four-hour restart would allow
him to restart work at 6 a.m. Monday, thus allowing him to
start work at the same time of day he started on Saturday.
Moreover, continued the agency, the restart provision will
enable drivers the flexibility to take their sleep during the
 22

day, and enable them to drive at night, when the number of
cars on the road is fewest. Id.
While the agency’s explanation seems sound enough as far
as it goes, it does not even acknowledge, much less justify,
that the rule, as petitioners point out and as explained above,
dramatically increases the maximum permissible hours driv-
ers may work each week. That increase is likely an ‘‘impor-
tant aspect of the problem.’’ State Farm, 436 U.S. at 43.
And the agency’s failure to address it, accordingly, makes this
aspect of the rule’s rationality questionable.

III. Conclusion
For the reasons given above, we vacate the rule in its
entirety and remand to the agency for proceedings consistent
with this opinion.