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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 appearance.

 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 petitioners.

Stephen L. Oesch, Shari T. Kendall, and Michele McDowell

Fields were on the brief for amicus curiae Insurance Institute 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 Counsel, Federal Motor Carrier Safety Administration.

Robert Digges, Jr. argued the cause for intervenors American 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 appearances.

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 operators. For the reasons more fully set out below, we agree

with petitioners that the rulemaking was arbitrary and capricious, because the FMCSA failed to take account of a statutory 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 statute 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 provided 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 recording devices, rest and recovery cycles, fatigue and

stress in longer combination vehicles, fitness for duty,

and other appropriate regulatory and enforcement countermeasures 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 motor vehicles, the petition before us addresses the impact of

the rule on long-haul truck drivers. The FMCSA promulgated 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 commercial 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 prohibited 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 fifteenhour 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 ‘‘programmed’’ 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 physiologically and cognitively least able. That vulnerability of drivers,

in turn, creates a substantial risk of substandard and potentially 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 onduty 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. (Separate 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, assuming 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 onduty 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 maximum cycle, the agency reasoned, better approximated circadian 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 offduty 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 ‘‘increases 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’ sleeperberth 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 ‘‘onduty’’ 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 fiftysix hours off-duty each week, covering two consecutive periods 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 – ‘‘circadianoptimal 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 logbooks to monitor their adherence to the new regulatory

requirements. Id. at 25,598. Those recorders would automatically 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 offduty 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 discussed, 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 maximum 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), however, had a twenty-four-hour daily cycle if they maximized

working hours and minimized off-duty time (ten hours). Following 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 proposed 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. Instead of a mandatory weekend, the agency allowed a thirtyfour-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 consecutive days, thereby allowing them to obtain adequate restorative 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 increased 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 contrast, allowed drivers to work more hours if they took thirtyfour 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 restructuring 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 fivehour minimum the NPR’s recommendation would have required 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 existing 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 capricious 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 objections 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 mandated 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 statutorily mandated factor, by definition, is an important aspect of

any issue before an administrative agency, as it is for Congress in the first instance to define the appropriate scope of

an agency’s mission. When Congress says a factor is mandatory, that expresses its judgment that such a factor is important. 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 conclude 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 agency may of course think that these and other effects on drivers

are not problematic (or are outweighed by other considerations, 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 dispositive 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 decision 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 mandated 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 concerns. 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 truckers’ 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 conducted. Id. at 22,471.

We have our doubts about whether these two justifications

are legally sufficient. The agency freely concedes that ‘‘studies 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 documented ill effects from the increase.

The agency did refer generally to studies, but that generalized 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 rulemaking 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 provision. Even assuming that the agency had adequately documented the beneficial effects from the decreased daily driving-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 compared 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 questionable value in justifying the increase in daily driving time.

The exponential increase in crash risk that comes with driving greater numbers of hours, presumably caused by time-ontask 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, ‘‘geometrically,’’ 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 entirely. 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 costbenefit 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 justifications for nevertheless permitting drivers to obtain the required 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 problem 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 vehicles 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 exception.

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 appropriate.

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 sleeperberth reduces the importance of the length of the uninterrupted 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 industry,’’ 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 performance, not a design, standard, enforcement officials ‘‘would

have to waste time and effort mastering incompatible readout 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 devices, rest and recovery cycles, fatigue and stress in

longer combination vehicles, fitness for duty, and other

appropriate regulatory and enforcement countermeasures 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 Dictionary 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. Regulators 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 regulations, 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 probability eminently possible. The agency has offered no good

reason for treating this problem with such passivity.

Without such a cost-benefit analysis, accounting for benefits 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 drivers may work each week. That increase is likely an ‘‘important 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.