 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued March 15, 2013                 Decided August 2, 2013

                        No. 12-1092

         AMERICAN TRUCKING ASSOCIATIONS, INC.,
                     PETITIONER

                             v.

  FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION AND
             UNITED STATES OF AMERICA,
                   RESPONDENTS

  OWNER-OPERATOR INDEPENDENT DRIVERS ASSOCIATION,
                    INC., ET AL.,
                   INTERVENORS


                Consolidated with 12-1113


       On Petitions for Review of a Final Rule Issued
     by the Federal Motor Carrier Safety Administration


     Erika Z. Jones argued the cause for petitioner American
Trucking Associations, Inc. and intervenors in support of
petitioner. With her on the briefs were Adam C. Sloane,
Richard P. Caldarone, Prasad Sharma, Richard S. Pianka,
Paul D. Cullen, Sr., Paul Damien Cullen, Jr., Joyce E.
Mayers, Karyn A. Booth, John M. Cutler, Jr., and R. Eddie
Wayland.
                             2

     Richard P. Schweitzer and Craig M. Cibak were on the
brief for amici curiae American Bakers Association, et al. in
support of petitioner.

     Scott L. Nelson argued the cause for petitioners Public
Citizen, et al. With him on the briefs were Allison M. Zieve,
Henry M. Jasny, and Gregory A. Beck.

     William B. Trescott, pro se, was on the briefs for
intervenor in support of Public Citizen, et al.

     Jonathan H. Levy, Attorney, U.S. Department of Justice,
argued the cause for respondents. With him on the brief were
Stuart F. Delery, Acting Assistant Attorney General, Matthew
M. Collette, Attorney, Paul M. Geier, Assistant General
Counsel for Litigation, U.S. Department of Transportation,
and Peter J. Plocki, Deputy Assistant General Counsel for
Litigation.

     Erika Z. Jones, Adam C. Sloane, Richard P. Caldarone,
Prasad Sharma, Richard S. Pianka, Paul D. Cullen, Sr., Paul
Damien Cullen, Jr., Joyce E. Mayers, Karyn A. Booth, John
M. Cutler, Jr., and R. Eddie Wayland were on the brief for
intervenors American Trucking Associations, Inc. et al., in
support of respondents.

   Before: BROWN and GRIFFITH, Circuit Judges, and
RANDOLPH, Senior Circuit Judge.

    Opinion for the Court filed by Circuit Judge BROWN.

    In this case we consider two challenges to the 2011
Hours of Service (HOS) rule issued by the Federal Motor
Carrier Safety Administration (FMCSA). American Trucking
                               3
Associations, Inc. (ATA), petitioner in Case No. 12-1092,
asserts that the new safety-oriented provisions in the final
HOS rule are overly restrictive and costly. By contrast,
various public interest organizations and individual truck
drivers (collectively “Public Citizen”), petitioners in Case No.
12-1113, claim the rule is insufficiently protective of public
safety. The agency comes down squarely in the middle,
believing it got everything “just right.”

     Recognizing that the arbitrary and capricious standard is
“highly deferential” and “presumes agency action to be
valid,” Am. Wildlands v. Kempthorne, 530 F.3d 991, 997
(D.C. Cir. 2008), we conclude that what remains of the 2003
Final Rule after two remands and three rulemakings are
highly technical points best left to the agency. We therefore
generally affirm the rule and vacate only the agency’s
application of the 30-minute break to short-haul drivers.

                       I. BACKGROUND
     This protracted rulemaking traces its beginnings to 1999,
the year Congress passed the Motor Carrier Safety
Improvement Act, Pub. L. 106-159, 113 Stat. 1748, and
created the FMCSA. Tasked with making the nation’s roads
safer, the new agency’s first rulemaking proposed significant
revisions to the regulations that had governed trucking
operations since 1962. See Hours of Service of Drivers;
Driver Rest and Sleep for Safe Operations, 65 Fed. Reg.
25,540 (May 2, 2000) (2000 NPRM). That effort concluded
three years later in 2003 with the promulgation of a final rule
that increased the daily driving limit from 10 to 11 hours;
reduced the daily on-duty limit from 15 to 14 hours; increased
the daily off-duty requirement from 8 to 10 hours; and created
a new exception to the weekly on-duty limit known as the 34-
hour restart. See Hours of Service of Drivers; Driver Rest and
                                 4
Sleep for Safe Operations, 68 Fed. Reg. 22,456, 22,457 (April
28, 2003) (2003 Final Rule).

     But as is often the case, the interested public did not go
quietly. Trucking industry associations and safety-oriented
public interest groups long at odds with each other — and the
agency — pushed back against the rule. Public Citizen
challenged the 2003 Final Rule as arbitrary and capricious.
We agreed. See Public Citizen v. FMCSA, 374 F.3d 1209,
1216 (D.C. Cir. 2004). Because FMCSA had “failed to
comply with [the] specific statutory requirement” to “ensure
that . . . the operation of commercial motor vehicles does not
have a deleterious effect on the physical condition of the
operators,” 374 F.3d at 1216 (internal quotation marks
omitted), we vacated the rule in its entirety, id. at 1223.1 In
response, Congress enshrined the 2003 Final Rule as law until
FMCSA could promulgate a new rule, see Pub. L. No. 108-
310, 118 Stat. 1144 (2004), which the agency did in 2005, see
Hours of Service of Drivers, 70 Fed. Reg. 49,978 (Aug. 25,
2005) (2005 Final Rule).

     Nearly identical to its 2003 predecessor, the 2005 Final
Rule failed to win over agency critics. Interested groups again
challenged the rulemaking as arbitrary and capricious, and
this Court once more agreed. See Owner-Operator Indep.
Drivers Ass’n, Inc. v. FMCSA, 494 F.3d 188, 206 (D.C. Cir.
2007) (OOIDA). But rather than vacate the contested
provisions on broad grounds, we rested our holding on two
technical shortcomings: the agency’s failure to (1) timely
disclose its methodology for determining its time-on-task
multipliers, see id. at 201, and (2) “provide a reasoned

    1
       While the agency’s obvious oversight was “dispositive” of
petitioner’s challenge, certain “troubling” aspects of the rulemaking
led us to voice our broader concerns in dicta. Id. at 1217.
                               5
explanation for a number of the methodology’s critical
elements,” id. at 203.
     FMCSA responded in 2008 by reissuing the 2005 Final
Rule with supplemental explanations and analysis. See Hours
of Service of Drivers, 73 Fed. Reg. 69,567 (Nov. 19, 2008)
(2008 Final Rule). Only after dissatisfied parties sought
judicial review of the 2008 Final Rule did the agency agree to
undertake a more responsive rulemaking. This most recent
effort began with the 2010 notice of proposed rulemaking,
Hours of Service of Drivers, 75 Fed. Reg. 82,170 (Dec. 29,
2010) (2010 NPRM), and ended in 2011 when FMCSA
promulgated the final rule now before the Court. See Hours of
Service of Drivers, 76 Fed. Reg. 81,134 (Dec. 27, 2011) (2011
Final Rule). For our purposes, the 2011 Final Rule resembles
the earlier rules in all essential respects save for the addition
of several new, safety-enhancing provisions:

    • 30-Minute Off-Duty Break. The 2011 Final Rule bars
    truckers from driving past 8 hours unless they have had
    an off-duty break of at least 30 minutes.

    • Once-Per-Week Restriction. To prevent drivers from
    abusing the 34-hour restart, the 2011 Final Rule allows
    truckers to invoke the provision only once every 168
    hours (or 7 days).

    • Two-Night Requirement. To ensure that drivers using
    the 34-hour restart have an opportunity to get two nights
    of rest, the 2011 Final Rule also mandates that the restart
    include two blocks of time from 1:00 a.m. to 5:00 a.m.

See 2011 Final Rule at 81,135–36.

    Unsatisfied, industry associations and public interest
groups promptly petitioned for review.
                               6

                II. JURISDICTION & STANDING

     Because FMCSA is part of the Department of
Transportation, the Hobbs Act circumscribes our jurisdiction
to hear only those challenges brought by petitioners
“aggrieved” by the agency’s final order. 28 U.S.C. § 2344.
“Proof of such aggrievement requires a showing of both
Constitutional and prudential standing,” Burlington N. &
Santa Fe Ry. Co. v. Surface Transp. Bd., 403 F.3d 771, 775
(D.C. Cir. 2005), the burden of which falls squarely on
petitioners, see Grocery Mfrs. Ass’n v. EPA, 693 F.3d 169,
174 (D.C. Cir. 2012), as does the obligation to supplement the
record to the extent necessary, see Sierra Club v. EPA, 292
F.3d 895, 900 (D.C. Cir. 2002).

     Prudential standing can be resolved without much fuss.
As interested participants in the notice and comment process
below, both sets of petitioners have more than adequately
established their party status. It is equally clear that all fall
within the zone of interest protected by the statute. See, e.g.,
Reytblatt v. NRC, 105 F.3d 715, 721–22 (D.C. Cir. 1997).
Tougher is the question whether all the parties have satisfied
the Article III requirements — a concrete and particularized
injury shown to be caused by the defendant and capable of
judicial redress. See Lujan v. Defenders of Wildlife, 504 U.S.
555, 560–61 (1992). FMCSA says both sets of petitioners
have failed to provide the Court with sufficient evidence to
support a claim of constitutional standing, but we think the
agency only partially correct.

     An association “has standing to sue under Article III of
the Constitution of the United States only if (1) at least one of
its members would have standing to sue in his own right; (2)
the interest it seeks to protect is germane to its purpose; and
                                  7
(3) neither the claim asserted nor the relief requested requires
the member to participate in the lawsuit.” Rainbow/PUSH
Coal. v. FCC, 330 F.3d 539, 542 (D.C. Cir. 2003); see also
Hunt v. Wash. State Apple Adver. Comm’n, 432 U.S. 333, 343
(1977). We believe ATA, the lone petitioner in Case No. 12-
1092, has made such a showing. “[C]reated to promote and
protect the interests of the trucking industry,” the national
association has an obvious interest in challenging FMCSA
rulemaking that directly — and negatively — impacts its
motor carrier members. ATA Br. i.

     The three public interest group petitioners in Case No.
12-1113, however, have abandoned any claim to associational
standing. They have chosen instead to ride the jurisdictional
coattails of individual co-petitioner Dana E. Logan, a truck
driver “directly regulated by the challenged rule.” Public
Citizen Br. 25.2 As a consequence of this litigation strategy,
standing for all petitioners in Case No. 12-1113 rises and falls
with Logan’s two declarations, the only evidence of its kind
in the record. See Pub. Citizen Br. Add. B (Declaration I);
Pub. Citizen Reply Br. Add. (Declaration II).3

     2
         The public interest group petitioners have expressly
disclaimed reliance on Mildred A. Ball, a similarly situated truck
driver petitioner, see Public Citizen Reply Br. 4 (“Ms. Logan has
thus established the three familiar prerequisites to Article III
standing . . . . And when multiple petitioners join in a challenge to
agency action, the standing of one petitioner is enough. . . .”
(citations and internal quotation marks omitted)), and do not claim
either Logan or Ball as members of their organizations.
      3
        In relevant part, those declarations identify Logan as a cross-
country commercial driver subject to the HOS rules. Although she
tries “to avoid using the 34-hour restart provision to drive more
hours” and tries “to avoid driving the full 11 hours allowable per
shift whenever possible,” Declaration I, her employer sets a
schedule that sometimes requires her to do just that, see Declaration
                                 8

     Petitioners contend Logan’s standing to challenge both
the 11-hour allowance and the 34-hour reset is self-evident.
Not only is Logan regulated, but FMCSA “does not (and
could not reasonably) contest that having to work or drive
more hours is an injury-in-fact.” Public Citizen Reply Br. 4.
The agency concedes Logan’s status as an “individual truck
driver[] directly regulated by the HOS rules,” FMCSA Br. 18,
but questions the applicability of the traditional wisdom that
“there is ordinarily little question” of injury, causation, and
redress when “the plaintiff is himself an object of the action
(or forgone action) at issue,” Lujan, 504 U.S. at 561–62. The
challenged HOS provisions do permit truck drivers to drive or
work more hours than would otherwise be allowed, FMCSA
reasons, but nothing in the rule affirmatively requires Logan
to log those hours. As pled, Logan’s injury stems not from
FMCSA’s rulemaking, but from a work schedule that forces
her to utilize the hours-increasing provisions — something
her employer dictates, not the agency. See FMCSA Br. 18–19.

     This clever causation/redressibility argument shifts the
conversation toward the allegedly injurious actions of a third
party, a claim for which “much more is needed” to establish
standing, Lujan, 504 U.S. at 562, but we still think it flawed.
Cutting against the agency’s argument is the well-established
principle that standing will lie where “a plaintiff demonstrates
that the challenged agency action authorizes the conduct that
allegedly caused the plaintiff’s injuries, if that conduct would
allegedly be illegal otherwise,” Animal Legal Def. Fund, Inc.
v. Glickman, 154 F.3d 426, 440 (D.C. Cir. 1998), which was
obviously the case here. Much in the same way, we think it “a

II. In Logan’s view, the 34-hour restart “allows an amount of
driving that is unsafe” and the 11-hour period “is too long to drive
in a single shift.” Declaration I.
                                9
hardly-speculative exercise in naked capitalism” to suggest
motor carriers would respond to the hours-increasing
provisions by requiring their drivers to use them and work
longer days. Abigail Alliance for Better Access to
Developmental Drugs v. Eschenbach, 469 F.3d 129, 135
(D.C. Cir. 2006). If anything, FMCSA counted on that fact
when it increased driver hours and flexibility to help
counteract the imposition of new limits and costs elsewhere.
The agency cannot now ignore this reality.

    That does not mean our inquiry has come to an end,
however. Although satisfied with Logan’s standing to
challenge FMCSA’s decision to employ an 11-hour driving
allowance over her preferred 10, we cannot say the same
holds true for Logan’s broad challenge to the 34-hour restart.
Crucially, whereas Logan has been consistent in her criticism
of the 11-hour allowance, she expressed clear, unqualified
support for a circumscribed 34-hour restart in a March 4,
2011 comment submitted as part of the 2010 NPRM. As
reproduced in her declaration, Logan’s comment stated:

    I also like the one time a week re-start. In all of my years
    on the road I have never used [the 34-hour restart] more
    than once a week. However I think [the proposed once-a-
    week limitation on the 34-hour restart] is a good idea so it
    will not be misused.

Declaration I. The parties pay little heed to this concession in
their briefing, but we think it significant in determining what
constitutes an injury for standing purposes.4


    4
       In a throwaway sentence, FMCSA takes Logan to task for
her about-face, calling standing to challenge the 34-hour restart
“particularly questionable.” Respondent Br. 19. Petitioners respond
with a brief footnote framing Logan’s comment as “reflect[ive of]
                                 10
     Given that Logan expressed support for a once-a-week
restriction she believed sufficient to eliminate abuse of the 34-
hour restart provision, we fail to see how she can now claim
injury from FMCSA’s decision to do as she advised and
restrict the use of the restart in the 2011 Final Rule to once
every 7 days.5 Is it possible Logan was always opposed to the
34-hour restart? Yes, of course. Is it possible Logan’s views
shifted in the intervening period such that she now thinks the
entire provision unwise? Probably. But hope as petitioners
might that we will take such a view of Logan’s concession,
we see nothing in the hopelessly sparse record that would
justify doing so. Not only did petitioners’ counsel think it
unnecessary to supplement Logan’s terse declarations and
attempt to explain these comments, they made no effort
whatsoever to demonstrate how Ball, the other individual
truck driver petitioner — and presumably someone not on the
record as supporting FMCSA proposals — was likewise
aggrieved. Perhaps counsel thought we would simply assume
standing as we did in the prior decisions, but we are unable do
so.6


her view that a limited restart was better than an unlimited one,”
which “certainly has no impact on her standing.” Public Citizen
Reply Br. 11 n.3. In our view, neither conclusory statement proves
to be of much help.
     5
       At an earlier January 22, 2010 FMCSA listening session,
Logan stated that use of the 34-hour restart was “adequate” when
used after 8 days on the road but not when she returns home “after
10 days or 14 days.” J.A. 365. Logan did not include these remarks
in her declaration, but we think the same result would obtain even if
she had.
     6
       We note that “courts are not bound by a prior exercise of
jurisdiction in a case where it was not questioned and it was passed
sub silentio.” Indep. Petroleum Ass’n of Am. v. Babbitt, 235 F.3d
588, 597 (D.C. Cir. 2001) (internal quotation marks omitted).
                                11
     For the foregoing reasons, then, we turn now to the
merits of Public Citizen’s challenge to the 11-hour driving
limit and ATA’s claims in their entirety.7

                          III. ANALYSIS

                      A. Standard of Review

    Where petitioners challenge agency decisions as arbitrary
and capricious, we apply the familiar touchstones set forth in
Motor Vehicle Manufacturers Ass’n of the United States v.
State Farm Mutual Automobile Insurance Co., 463 U.S. 29
(1983). Deferring as appropriate to the agency’s expertise and
looking only for “a rational connection between the facts
found and the choice made,” id. at 43 (internal quotation
marks omitted), we remain ever mindful that in performing “a
searching and careful inquiry into the facts, we do not look at
the [agency’s] decision as would a scientist, but as a
reviewing court exercising our narrowly defined duty of
holding agencies to certain minimal standards of rationality,”
Nat’l Envtl. Dev. Ass’n’s Clean Air Project v. EPA, 686 F.3d
803, 810 (D.C. Cir. 2012) (internal quotation marks omitted).

                      B. 34-Hour Restart

     Having determined that Public Citizen is without
standing to challenge FMCSA’s decision to include a 34-hour
restart, we are left only to deal with ATA’s far more
circumscribed objections to the two limits on the restart’s use:



    7
        Pro se intervenor William B. Trescott offers nary an
argument in his briefs as to why his lobbying activities would
establish standing. For this reason, we need not reach the merits of
his arguments.
                              12
the once-per-week (168-hour) restriction and the two-night
(1:00 a.m. to 5:00 a.m.) requirement.

               i. Once-Per-Week Restriction

     One ostensible problem with the 34-hour restart is that
hours-maximizing drivers could strategically employ the
restarts to increase the amount of time they spend driving or
on duty. A once-per-week restriction forces drivers to wait the
full 168 hours before invoking the provision a second time.
The math is byzantine, but the net effect of the limit is to
reduce the maximum number of hours a driver could spend
driving or on duty per 7- or 8-day period. “[T]he maximum
driving hours per 7 days,” for example, would drop from 73.9
hours “down to 70 hours, a small but not a trivial reduction.”
2011 Final Rule at 81,158.

     Since the agency previously argued in favor of an
unlimited 34-hour restart, the administrative record reveals
some tension between earlier statements and the agency’s
present call for additional safety requirements. ATA
highlights these inconsistencies as proof the record will not
bear FMCSA’s current interpretation (or in the same vein, that
the agency has acted arbitrarily in failing to distinguish its
“prior positions”). See ATA Br. 36–37, 39. ATA directs its
weightiest challenge toward FMCSA’s shifting views
regarding the existence vel non of hour-maximizing drivers, a
concern FMCSA had initially dismissed as unlikely and
unrealistic. See, e.g., 2005 Final Rule at 50,022 (“FMCSA
believes the average driver is not, and cannot realistically,
drive and work the longer weekly hours, on a regular basis, as
described by some of the commenters.”); 2008 Final Rule at
69,570 (“Commenters have not provided nor has the Agency
seen any contrary evidence.”).
                              13
     FMCSA responds that “new evidence caused a change in
the agency’s view.” Respondent Br. 49. As explained in the
2010 NPRM, drivers and carriers disabused the agency of its
previously held views when they “stated at the listening
sessions and in their comments that, especially on the road,
drivers do indeed take the minimum restart allowed,” with
some carriers even acknowledging “that they have used the
restart to add one work shift a week.” 2010 NPRM at 82,182;
see also Respondent Br. 49 n.12. In light of these new
developments, we cannot say FMCSA acted arbitrarily or
capriciously in recalibrating the HOS regulation to reflect its
changed understanding of how the 34-hour restart is used in
practice. Agencies are free to change their views provided
they offer reasonable explanations and justifications for their
departure, see FCC v. Fox Television Stations, Inc., 556 U.S.
502, 515 (2009), which is exactly what FMCSA did here.8

                ii. Two-Night Requirement

     ATA’s broadest criticism operates with the greatest force:
the agency has long championed stability (or circadian
synchronization) — the maintenance of a consistent, 24-hour
daily schedule instead of a constantly shifting or rotating
schedule — but this rule is designed to result in circadian de-
synchronization. Because a 34-hour restart must now include
two 1:00 a.m.-to-5:00 a.m. periods, the rule strongly
encourages nighttime drivers who generally sleep during the
day to switch to nighttime sleep during a restart. See ATA Br.
43. While FMCSA concedes the dissonance, it notes that it
“never championed the maintenance of circadian rhythms
above all else.” Respondent Br. 54. The record amply

    8
     We have given due consideration to ATA’s other, scattered
arguments and found them wanting.
                              14
supports the point. When weighing the costs and benefits of a
44-hour restart that would likewise “encourage drivers to
operate on a rotating shift,” 2005 Final Rule at 50,024, the
agency observed “there is no conclusive scientific data to
guide it in determining which factor (recovery time vs.
circadian disruption) is more effective in alleviating fatigue,”
id. Even more compelling is the intervening 2010 study
concluding “that the 2-night provision works better than 1-
night to mitigate driver fatigue in nighttime drivers.” 2011
Final Rule at 81,156. ATA takes issue with the study’s
methodology and the conclusions FMCSA draws from it, see
ATA Br. 42, but we must unquestionably defer to an agency’s
expertise in weighing and evaluating the merits of scientific
studies, see, e.g., Transmission Access Policy Study Grp. v.
FERC, 225 F.3d 667, 714 (D.C. Cir. 2000).

     In sum, we think the agency has acted reasonably, if
incrementally, in tailoring the restart to promote driver health
and safety.

               C. 11-Hour Driving Allowance

     A decade after first proposing the 11-hour driving
allowance, the 2010 NPRM floated a possible return to a 10-
hour limit, then the agency’s “preferred option.” 2010 NPRM
at 82,171. But much to Public Citizen’s chagrin — and
ATA’s delight — the 11-hour limit prevailed. In announcing
FMCSA’s final decision, the 2011 Final Rule explained how
the agency had been “unable to definitively demonstrate that a
10-hour limit . . . would have higher net benefits than an 11-
hour limit.” 2011 Final Rule at 81,134 (emphasis added).
Public Citizen seizes on this language to contest FMCSA’s
decision as one “based on a misunderstanding of its
authority.” Public Citizen Br. 36. “By demanding proof of
cost effectiveness before adopting a rule that would improve
                              15
safety,” it reasons, FMCSA “did the opposite of what
Congress intended” when it limited the agency to consider
“costs only to the extent that is ‘practicable and consistent
with [its safety and driver health oriented] purposes.’ ” Id. at
38 (quoting 49 U.S.C. § 31136(c)(2)).

     The argument has some intuitive appeal, but we think
Public Citizen reads far too much into this introductory
language. FMCSA’s point is far more mundane than its
imprecise language would suggest: the agency ran the
cost/benefit analysis with an eye toward adopting the 10-hour
limit, but recognized that doing so would have been
unreasonable and unfounded on the record before it. FMCSA
can be criticized for using improvidently absolute and
unqualified language, but we cannot say its approach is
irreconcilable with congressional intent. This is clear when
one considers the rulemaking in its entirety and does not focus
exclusively on the largely perfunctory statements in the
opening summary. For the same reasons, we reject Public
Citizen’s related claim that FMCSA based its decision on an
erroneous view of the law when it suggested elsewhere in the
introduction that there were not “adequate and reasonable
grounds under the Administrative Procedure Act for adopting
a new regulation” because there was an “absence of
compelling scientific evidence demonstrating the safety
benefits of a 10-hour driving limit, as opposed to an 11-hour
limit.” 2011 Final Rule at 81,135.

     Public Citizen advances two additional challenges to the
11-hour limit that call into question the propriety and
sufficiency of FMCSA’s cost/benefit analysis. See Public
Citizen Br. 39–41, 47–52. As explained in Section III.E.,
infra, we think those criticisms misguided.
                              16
                    D. 30-Minute Break

    The HOS regulations cover not only the “long-haul”
truck drivers who regularly sacrifice days, weeks, and even
months with their families to make the American economy go
round, but “short-haul” drivers as well, those who operate
within a local area. See 2011 Final Rule at 81,141. “In
general,” however, “short-haul trucking work has far more in
common with other occupations than it does with regional or
long-haul trucking.” 2011 Final Rule at 81,175. As typified by
the local FedEx delivery driver, id. at 81,145, short-haul
positions tend to be “5-day-a-week jobs” with typical “8 to 10
hour[]” work days and, quite often, an opportunity for
overtime, id. at 81,175. “Most of the work” tends to be
“regular in character” with drivers going to “basically the
same places and do[ing] the same things every day.” Id. The
record also tells us that “[s]hort-haul drivers rarely drive
anything close to 11 hours, and available statistics show that
they are greatly under-represented in fatigue-related
accidents.” 2005 Final Rule at 49,980.

     It should come as no surprise then that FMCSA has
historically distinguished between long-haul and short-haul
operations. Under 49 C.F.R. § 395.1(e)(2), for example, short-
haul drivers who operate vehicles that do not require a
commercial driver’s license and who operate “within a 150
air-mile radius of the location where the driver reports to and
is released from work,” and, among other things, “return[] to
the normal work reporting location at the end of each duty
tour,” had greater flexibility in scheduling. Two days a week
they could drive between the 14th and 16th hour after coming
on duty, see 49 C.F.R. § 395.1(e)(2)(iv), whereas long-haul
drivers could never drive beyond the 14th hour after coming
on duty, see 49 C.F.R. § 395.3(a)(2). Qualifying short-haul
drivers were also exempted from the requirement that drivers
                              17
keep logs recording their “duty status for each 24 hour
period.” Id. § 395.8(a). In most other respects, however,
short- and long-haul drivers were bound by the same HOS
provisions

     It was against this backdrop that FMCSA’s 2010 NPRM
proposed expanding the twice-a-week 16-hour extension to
long-haul drivers as well. Because doing so would render
§ 395.1(e)(2) largely superfluous, the agency also broached
the idea of eliminating the exemption altogether:

       In order to simplify the HOS regulations, FMCSA is
       considering rescinding paragraph (e)(2) and requiring
       the drivers who now use it to comply with the standard
       HOS limits. Although we have not formally included
       such a proposal in this NPRM, the Agency seeks
       comments on the effect of eliminating paragraph
       (e)(2). . . . FMCSA has little hard information about
       operations currently conducted under paragraph (e)(2);
       we invite drivers and carriers that utilize this provision
       to explain how a decision to remove it would affect
       them.

2010 NPRM at 82,184.

     When all was said and done, however, the 2011 Final
Rule opted not to disturb the status quo. See 2011 Final Rule
at 81,136 (“Because FMCSA has dropped the proposed 16-
hour provision, the concerns about confusion are moot.”).
The § 395.1(e)(2) exemption thus survived, but short-haul
drivers did not emerge from the rulemaking unscathed.
FMCSA imposed the requirement of a 30-minute off-duty
break on both long-haul and short-haul truckers. ATA did not
take kindly to the new requirement, which it now challenges
on three grounds.
                              18

     ATA first attacks the 2011 Final Rule as “procedurally
invalid,” ATA Br. 50, claiming the final rule was not, as this
Court requires, a “logical outgrowth” of the proposed
rulemaking, see City of Portland v EPA, 507 F.3d 706, 715
(D.C. Cir. 2007). Although ATA gets the standard right, we
think its conclusion wrong. The substance of the NPRM was
clear: the proposed change to the existing HOS regulations
would impose an off-duty break of “at least 30 minutes.”
2010 NPRM at 82,171. That FMCSA would apply that
requirement to short-haul truckers was obviously a logical
outgrowth of the NPRM, which proposed eliminating the
§ 395.1(e)(2) exemption and requiring short-haul drivers to
“comply with the standard HOS limits.” Id. at 82,184. The
only way ATA can circumvent this reality is to manufacture
ambiguity in the proposal’s scope, and that is exactly what the
association attempts to do by relying heavily — if not
exclusively — on the NPRM’s discussion of the § 395.1(e)(2)
exemption. See supra. As best we understand the contention,
ATA believes interested parties could not have reasonably
anticipated FMCSA’s decision to apply a 30-minute off-duty
break to short-haul drivers because doing so would constitute
a narrowing of § 395.1(e)(2), and the NPRM proposed only
the elimination of that exemption, not a narrowing. See ATA
Br. 50.

     We fail to see how any reasonable commentator would
have read the NPRM to suggest the agency would not do what
it was otherwise free to: apply the 30-minute break
requirement to short- and long-haul truckers alike. That
several interested parties expressly recognized this possibility
only confirms as much. See, e.g., JA 742 (comment opposing
“a 30-minute driver break within the first seven hours of
driving time” for “short haul heating oil and propane
drivers”); 2011 Final Rule at 81,145 (referring to comment by
                              19
FedEx that “a 30-minute rest break by the 7th hour after
coming on duty would . . . hinder local package pickup and
delivery drivers”).

     Changing gears, ATA next argues FMCSA acted
arbitrarily and irrationally by failing to explain the agency’s
decision to apply the 30-minute break requirement to short-
haul drivers. See ATA Br. 50–51. This claim has far more
traction. Despite the many paragraphs scattered throughout
the multiple rulemakings distinguishing short- and long-haul
trucking both in degree and in kind, see, e.g., 2011 Final Rule
at 81,141; 2010 NPRM at 82,175; 2005 Final Rule at 49,995–
96; 2003 Final Rule at 22,482, the 2011 Final Rule contains
not one word justifying the agency’s decision to apply the
new requirement to the unique context of short-haul
operations.9 The agency responds meekly, suggesting that the
general explanation for the necessity of a 30-minute break
“applies, on its face, to short-haul as well as long-haul
drivers.” Respondent Br. 79. Because such conclusory, post-
hoc rationalization falls far short of what is required under
State Farm, we think the offending requirement must be
vacated. See 463 U.S. at 50.

     Finally, ATA challenges as arbitrary and capricious
FMCSA’s decision to impose an “off-duty” break. In the
association’s view, there is no support for the agency’s claim
that “off-duty breaks yield greater reductions in crash risk”
than on-duty, non-driving breaks. ATA Br. 46. We find no
merit to the claim. FMCSA has more than adequately
supported its choice by referencing an intervening 2011 study
concluding that “off-duty” breaks provided the “greatest

    9
      Nor do we read the agency’s 2010–2011 Regulatory Impact
Analysis, JA 822–1061, as having adequately considered the cost
the 30-minute off-duty break would have on short-haul operators.
                             20
benefit.” 2011 Final Rule at 81,154; see also JA 790 (“[A]ny
break was better than no break, though an off-duty break
provided the most benefit.”). ATA is certainly free to quarrel
with the study’s methodology, but given our deference to the
agency in such matters, we have no reason to doubt that
FMCSA made a “reasoned decision based on reasonable
extrapolations from some reliable evidence.” NRDC v. EPA,
902 F.2d 962, 968 (D.C. Cir. 1990) (internal quotation marks
omitted).

                     E. Cost & Benefits

     To better account for uncertainty, the agency developed a
cost/benefit model that toggled multiple variables —
including baseline sleep assumptions (low, medium, or high),
baseline percentage of crashes caused by fatigue (7%, 13%,
18%), and discount rates (3% or 7%) — to “calculate[] the net
benefits for . . . 18 different scenarios.” Respondent Br. 69.
FMCSA repeated this process for each particular constellation
of regulations under consideration and then compared the
different results. Predictably, Public Citizen and ATA take
issue with nearly every aspect of the analysis, beginning with
the variables used.

     In evaluating petitioners’ challenges, however, we keep
in mind our obligation to review an agency’s cost/benefit
analysis deferentially. It is not for us to undertake our own
economic study and substitute the Court’s views for those of
the agency. See, e.g., Nat’l Ass’n of Home Builders v. EPA,
682 F.3d 1032, 1040 (D.C. Cir. 2012); Nat’l Wildlife Fed’n v.
EPA, 286 F.3d 554, 563 (D.C. Cir. 2002). Thus, while a
“serious flaw” or otherwise arbitrary and capricious reasoning
can crash an agency’s cost/benefit analysis, Nat’l Ass’n of
Home Builders, 682 F.3d at 1040, petitioners’ “burden to
show error is high,” id. (internal quotation marks omitted).
                               21
Having carefully considered both the briefing and the record,
we cannot say that burden has been met.

     Where the petitioners themselves disagree on something
as fundamental as the percentage of crashes that can be
classified as fatigue-related, compare ATA Br. 20–21 (at or
around 2.2%), with Public Citizen Br. 44 (at least 13% with
some studies placing the figure at over 30%), we hardly think
it proper to second-guess the agency’s decision to employ a
7%-to-18% range. That deference translates equally to
FMCSA’s choices regarding baseline sleep assumptions, a
determination dependent on parsing studies far beyond our
ken, as well as discount rates, see Ohio v. U.S. Dep’t of the
Interior, 880 F.2d 432, 465 (D.C. Cir. 1989) (deferring to
agency’s decision to adopt a particular discount rate, calling it
“first and foremost a policy choice”). To be sure, petitioners
are not without their broader challenges to the agency’s
cost/benefit analysis, but these largely superficial arguments
establish at most that FMCSA made unwise policy decisions,
not that the agency acted irrationally or contrary to law.

                        IV. Conclusion

      It is often said the third time’s a charm. That may well be
true in this case, the third of its kind to be considered by the
Circuit. With one small exception, our decision today brings
to an end much of the permanent warfare surrounding the
HOS rules. Though FMCSA won the day not on the strengths
of its rulemaking prowess, but through an artless war of
attrition, the controversies of this round are ended.

    For the foregoing reasons, we grant ATA’s petition in
part and vacate the rule insofar as it subjects short-haul
drivers to the 30-minute off-duty break requirement. In all
                            22
other respects, the petitions of both ATA and Public Citizen
are

                                                    Denied.
