               IN THE SUPREME COURT OF IOWA
                              No. 17–0686

                          Filed April 27, 2018


CITY OF DES MOINES, IOWA,

CITY OF MUSCATINE, IOWA,

and

CITY OF CEDAR RAPIDS, IOWA,

      Appellants,

vs.

IOWA DEPARTMENT OF TRANSPORTATION
and IOWA TRANSPORTATION COMMISSION,

      Appellees.



      Appeal from the Iowa District Court for Polk County, Scott D.

Rosenberg, Judge.



      Three cities appeal a district court order upholding administrative

rules issued by the Iowa Department of Transportation. REVERSED AND

REMANDED.



      Michelle R. Mackel-Wiederanders and Carol J. Moser, Des Moines,

Douglas A. Fulton, Matthew S. Brick, and Erin M. Clanton of Brick Gentry,

P.C., West Des Moines, Elizabeth D. Jacobi and James H. Flitz, Cedar

Rapids, for appellants.
                                2

      Thomas J. Miller, Attorney General, David S. Gorham, Special

Assistant Attorney General, and Richard E. Mull, Assistant Attorney

General, for appellees.
                                      3

MANSFIELD, Justice.

      We must determine whether the Iowa Department of Transportation

(IDOT) had the statutory authority to promulgate administrative rules

regulating automated traffic enforcement (ATE) systems located along

primary roads.     See Iowa Admin. Code ch. 761—144 (2014).               The

enforcement of these rules resulted in three cities being ordered to relocate

or remove several of their ATE cameras.

      The issue presented is the reach of the administrative state: Before

the executive branch can adopt a rule with the force and effect of law, how

much groundwork must be laid by the legislative branch? After all, article

III, section 1 states that “[t]he legislative authority of this state shall be

vested in a general assembly . . .”—not the executive branch. Iowa Const.

art. III, § 1. Article III, section 1 also states that “no person charged with

the exercise of powers properly belonging to one of these departments shall

exercise any function appertaining to either of the others, except in cases

hereinafter expressly directed or permitted.” Id.

      On our review, we find that the IDOT did not have authority from

the legislature to issue rules regulating ATE systems. The IDOT’s specific

grants of authority are in other areas and do not support the rules.

Moreover, any general authority over “regulation and improvement of

transportation” is too broad to sustain the rules—particularly in light of

the specific grants of authority in other areas. See Iowa Code § 307.2

(2013).   Accordingly, we conclude the rules are invalid and cannot be

enforced against the cities.   Therefore, we reverse the judgment of the

district court and remand for further proceedings.

      I. Facts and Procedural Background.

      This dispute is between the IDOT and three cities—Cedar Rapids,

Des Moines, and Muscatine (the Cities). The Cities have installed ATE
                                             4

systems on primary roads within their boundaries. 1 The IDOT has sought

to regulate and limit those ATE systems through administrative rules.

       A. The Installation of the Cities’ ATE Systems. Until 2014, the

IDOT had no formal rules governing ATE systems but instead relied on

informal guidelines.        In 2010, working within these guidelines, Cedar

Rapids obtained the IDOT’s written agreement that the city could install

ATE equipment. Cedar Rapids placed these systems in various locations

within its city limits. These places included Interstate 380 and 1st Avenue

East at the intersection of 10th Street. Both I-380 and 1st Avenue East

are considered primary roads.

       Early in 2011, Muscatine also obtained the IDOT’s written

agreement to install ATE equipment within its limits, following a study of

accident data and speeding and red-light surveys. The locations included

two intersections along Highway 61, a primary road.

       Later that year, Des Moines also received IDOT’s agreement that it

could install ATE cameras to monitor red-light running and speeding.

These included an ATE system to detect speeding vehicles traveling

eastbound on Interstate 235, between 42nd Street and Polk Boulevard. I-

235 is also a primary road. The specific location on I-235 was chosen

because of traffic flow, highway grade, and layout, which the city

maintained made it more difficult for officers to monitor speed safely from

their patrol cars.

       1ATE   systems use automated cameras to record motorists who commit traffic
violations, such as speeding or running a red light. After the vehicle and its license
number have been photographed, a citation is sent to the registered owner of the vehicle.
See, e.g., Des Moines, Iowa, Code of Ordinances § 114-243 (2018). Typically, only a fine
is charged. See, e.g., id. There is no effect on the motorist’s driving or insurance record,
and it is only a civil infraction. Also, the ATE systems generally result in a speeding
citation only when the motorist is driving a certain threshold amount above the speed
limit—such as more than ten miles per hour above the limit. See, e.g., Muscatine, Iowa,
City Code § 7-5-5 (2018).
                                    5

       IDOT’s standard agreements—which each of the Cities executed—

stated that the agency reserved the right to “[r]equire the removal of such

traffic control device upon thirty days’ written notice.    Either lack of

supervision,   inadequate    enforcement,    unapproved    operation,   or

intolerable congestion shall be considered sufficient reason to require

removal.”

       B. The IDOT’s Rulemaking.        On October 2, 2013, the IDOT

commenced a rulemaking proceeding to regulate and restrict ATE

placement and usage on primary roadways. See Iowa Code § 17A.4. In

accordance with requirements of the Iowa Administrative Procedures Act,

the IDOT published proposed rules and accepted written comments on

them. See id. § 17A.4(1)(a)–(b).

       Among other things, the proposed rules provided that ATE systems

“shall only be considered after other engineering and enforcement

solutions have been explored and implemented,” “should not be used as a

long-term solution for speeding or red-light running,” and “should only be

considered in extremely limited situations on interstate roads because

they are the safest class of any roadway in the state and they typically

carry a significant amount of non-familiar motorists.” Notice of Intended

Action, Admin. Rules Review Comm. 1037C (IDOT Oct. 2, 2013),

https://www.legis.iowa.gov/docs/aco/arc/1037C.pdf.         The   proposed

rules also required advance approval by the IDOT and a detailed

“justification report” for any ATE system. Thereafter, localities would be

required to submit detailed annual evaluations to assist the IDOT in

reevaluating each ATE system and deciding whether to allow its continued

use.
                                           6

      Many comments were submitted expressing sharply divergent

viewpoints. 2    Most commenters did not discuss the actual rules but

addressed the pros and cons of ATE systems generally. For example:

           “I strongly support the use of traffic cameras in Cedar
      Rapids—specifically on I380. They are working!”

           “In general, I am against the indiscriminate use of ‘spy
      cameras’ as a means to collect massive fines from drivers.”

             “I like the idea of traffic cameras for speeding and red
      lights. I believe they do help to sa[v]e lives.”

            “I am in total agreement of getting rid of photo enforced
      speed cameras in Iowa. It is an invasion of privacy. Thank
      you for using common sense on this issue.”

            “I welcome fewer restrictions on the installation of
      speed and red-light cameras. It’s the easiest way to keep
      drivers honest and legal. And that’s good for everyone.”

           “I am totally against traffic cameras and think they
      should be outlawed.”

             “Anything to get people to obey traffic laws is a good
      thing, even if it is unpopular. Calling the cameras distracting
      to drivers just to get rid of them is a cheap shot. KEEP THE
      CAMERAS.”

            “I see ABSOLUTELY NO value in traffic cameras placed
      on the highway.”

      Some commenters offered more specific suggestions.                One

commenter urged that

      [s]peed cameras should not be placed where there is a sudden
      reduction in the speed limit. It is dangerous to have a speed
      sign reducing speed a short distance from the camera. The
      locals know to reduce their speed and start slamming on [their
      brakes], which is not safe for traffic.

      Along the same lines, another commenter recommended “that the

Department additionally restrict ATEs’ placement in locations where a

higher speed zone is transitioning to a lower speed zone.” Yet another

      2The   IDOT received a total of 164 written comments.
                                      7

commenter proposed that ATE systems “[n]ot be placed within 1,000 feet

of either side of a posted speed limit sign.”

      On October 30, the IDOT held a public hearing to afford interested

persons an opportunity to speak out on the proposed rules.           At the

hearing, representatives of the Cities, in addition to other officials and

members of the public, made oral presentations.         A total of thirteen

persons spoke.

      Again, the subject of limiting the use of speed cameras within a

certain distance of new speed limits came up. For example, one speaker

expressed concerns about municipalities installing ATE systems “in areas

where the speed is going from a faster speed zone to a slower speed zone .

. . because those are areas where more people are likely to slam on their

brakes, and it would be . . . more dangerous.”

      The IDOT held a subsequent meeting on December 10 to present the

final rules and detail the feedback it had received throughout the process.

At this time, the IDOT unveiled modifications to the rules. These included

a “1000-foot rule”—i.e., that ATE equipment could not be stationed within

1000 feet of a speed limit change.          The IDOT explained that this

modification was in response to prior comments.

      In most other respects, the final rules mirrored the initial rules the

IDOT had proposed in October. Thus, all ATE locations on the primary

road system had to be approved by the IDOT. Iowa Admin. Code r. 761—

144.4(3).   The final rules contained a requirement that any “local

jurisdiction requesting to use an automated traffic enforcement system on

the primary road shall provide the department a justification report.” Id.

r. 761—144.5(1). Such report needed to include documentation as to “why

the area is a high-crash or high-risk location.” Id. r. 761—144.5(1)(a).

According to the rules, ATE systems “should only be considered in
                                       8

extremely limited situations on interstate roads because they are the safest

class of any roadway in the state and they typically carry a significant

amount of non-familiar motorists.” Id. r. 761—144.4(1)(c). After the ATE

equipment was installed, the rules required “each local jurisdiction with

active automated enforcement on Iowa’s primary highway system [to]

evaluate the effectiveness of its use” on an ongoing basis. Id. r. 761—

144.7(1). The annual evaluation must

           (1) Address the impact of automated enforcement
      technology on reducing speeds or the number of red-light
      running violations for those sites being monitored.

            (2) Identify the number and type of collisions at the sites
      being monitored, listing comparison data for before-and-after
      years. If the system includes intersection enforcement, only
      the monitored approaches should be included in the
      evaluation.

            (3) Evaluate and document the automated traffic
      enforcement system’s impact on addressing the critical traffic
      safety issue(s) listed in the justification report if a justification
      report was part of the system’s initial approval process.

            (4) Provide the total number of citations issued for each
      calendar year the system has been in operation.

            (5) Certify that the calibration requirements of subrule
      144.6(4) have been met.

Id. r. 761—144.7(1)(a).

      The IDOT would determine whether use of the ATE system would

continue. Id. r. 761—144.8. “Continued use [would] be contingent on the

effectiveness of the system, appropriate administration of it by the local

jurisdiction, the continued compliance with these rules, changes in traffic

patterns, infrastructure improvements, and implementation of other

identified safety countermeasures.” Id. r. 761—144.8(1). Additionally, the

department explicitly “reserve[d] the right to require removal or
                                     9

modification of a system in a particular location, as deemed appropriate.”

Id. r. 761—144.8(2). The rules became effective February 12, 2014.

      C. The IDOT’s Subsequent Directives to Remove Certain ATE

Systems. Once the ATE rules became effective, each city submitted an

evaluation to the IDOT in an effort to justify the continued presence of the

cameras. Cedar Rapids provided crash data showing that crashes at 1st

Avenue and 10th Street had remained roughly constant since the

installation of the ATE systems.     However, on I-380 there had been

declines both in overall crashes and, especially, personal injury crashes.

Whereas one fatal crash had occurred in 2008 and two in 2009, no fatal

crashes had occurred in the relevant area of I-380 since the ATE cameras

were installed.

      Muscatine reported that totaling the five intersections where ATE

equipment had been installed, crashes had declined significantly overall.

In 2010, there had been thirty-four motor vehicle crashes including nine

injury crashes; by contrast, during the year 2013, there had been nineteen

crashes, of which four were injury crashes.

      Des Moines’s report also argued that its ATE systems had had a

positive safety impact. Regarding the I-235 location, the report concluded

that “the total number of accidents on I-235 in this area (4700 block to

4200 block) have decreased since the implementation of our camera

program.”

      Nonetheless, the IDOT ordered all of the Cities to disable or move

some of their ATE equipment. Cedar Rapids was told to disable its ATE

speed detection system at the intersection of 1st Avenue and 10th Street

because it violated the 1000-foot rule. The IDOT also told Cedar Rapids

to move, remove, or disable its ATE cameras on I-380 either because of the

1000-foot rule or because “[t]he location of the camera is well beyond the
                                    10

‘S’ curve [on I-380] and therefore beyond the area of concern.” The IDOT

further cited Iowa Administrative Code rule 761—144.4(1)(c) regarding the

limited use of ATE systems on interstate roadways.

      Muscatine was ordered to remove its ATE camera from Highway 61

at University because it violated the 1000-foot rule, because there were a

high number of citations, and because crashes had increased at this

particular location since the camera was installed.

      The IDOT directed Des Moines to remove its ATE camera from I-235

as well. Although it acknowledged a reduction in crashes since the camera

was activated, it pointed to its own rule that ATE should only be considered

in extremely limited situations on interstate highways and observed that

“[t]his location experiences a low crash rate.”    It also noted the high

number of citations.

      Each city appealed, and the department director upheld each

decision.

      D. The Consolidated Petition for Judicial Review. On June 9,

10, and 11, 2015, Des Moines, Muscatine, and Cedar Rapids respectively

filed separate petitions for judicial review under Iowa Code chapter 17A.

These actions challenged the IDOT’s actions on various grounds, including

(1) infringement of the Cities’ home rule authority; (2) lack of statutory

authority for the IDOT to promulgate the rules; (3) a claim that the IDOT

did not follow proper procedure in promulgating the rules, especially

because the original, proposed rules had not contained a 1000-foot rule;

and (4) a claim that the IDOT’s directives under the rules to remove or

disable specific ATE equipment were arbitrary and capricious. The actions

were later consolidated into a single proceeding in the Iowa District Court

for Polk County.
                                     11

      On March 27, 2017, the district court held a hearing, and the court

subsequently issued an order on April 25.

      The district court’s order upheld both the IDOT’s rules and its

decisions based on those rules.      In dismissing the Cities’ home rule

argument, the court noted, “Pursuant to Section 306.4(1), the IDOT

implemented rules governing the minimum requirements for ATEs, their

evaluation, and their subsequent removal if necessary. Iowa Admin. Code

r. 761—144. Therefore, state law, through the IDOT administrative rules,

controls.”

      The court also found that the IDOT had sufficient authority under

the Iowa Code to promulgate the subject ATE rules. It stated,

             The “jurisdiction and control over the primary roads
      shall be vested in the [IDOT].” [Iowa Code] § 306.4(1). To carry
      out these statutory provisions, the IDOT adopted rules
      regulating ATEs emphasizing safety. See Iowa Admin. Code r.
      761—144.6(1).         This is consistent with regulating
      obstructions in highway right-of-ways; the construction,
      improvement, operation or maintenance of any highway; and
      limiting cities’ obstruction of a street or highway which is used
      as an extension of a primary road. See Iowa Code Chapter
      318; Iowa Code §§ 306.4, 321.348.

(First alteration in original.)

      The district court further concluded that the rules had been

promulgated in accord with a proper procedure, noting,

      At the meetings and during the public hearing, comments
      specifically citing the 1,000ft rule were submitted. Therefore,
      the 1,000ft rule is a direct result of public comments made
      and is, at the very least, a logical outgrowth of overall public
      comments. Since final administrative rules may differ from
      proposed rules, an additional notice and comment period is
      not required and the IDOT decisions and orders pursuant to
      the rule are valid.

      Finally, the district court concluded that the application of the rules

to the Cities’ ATE systems complied with chapter 17A because the IDOT’s
                                     12

review of the statistics and data was comprehensive, reviewing more than

simply speed data or crash data. The court concluded that the IDOT’s

actions were reasonable and logical and thus did not violate chapter 17A.

      The Cities appealed the district court’s rulings on all of these issues,

and we retained the appeal.

      II. Standard of Review.

      “Judicial review of agency decisions is governed by Iowa Code

section 17A.19.” Brakke v. Iowa Dep’t of Nat. Res., 897 N.W.2d 522, 530

(Iowa 2017) (quoting Kay-Decker v. Iowa State Bd. of Tax Review, 857

N.W.2d 216, 222 (Iowa 2014)). We use the standards set forth in section

17A.19(10) “to determine if we reach the same results as the district court.”

Id. (quoting Renda v. Iowa Civil Rights Comm’n, 784 N.W.2d 8, 10 (Iowa

2010)).

      To resolve whether the IDOT had authority to promulgate the ATE

rules, we must determine whether its action was “[b]eyond the authority

delegated to the agency by any provision of law or in violation of any

provision of law.” Iowa Code § 17A.19(10)(b).

      Historically, we have said that an agency rule is “presumed valid

unless the party challenging the rule proves ‘a “rational agency” could not

conclude the rule was within its delegated authority.’ ” Meredith Outdoor

Advert., Inc. v. Iowa Dep’t of Transp., 648 N.W.2d 109, 117 (Iowa 2002)

(quoting Milholin v. Vorhies, 320 N.W.2d 552, 554 (Iowa 1982) (en banc));

see also Brakke, 897 N.W.2d at 533.

      However, “[t]he power of the agency is limited to the power granted

by statute.” Brakke, 897 N.W.2d at 533. In Brakke, we emphasized that

“ultimately the interpretation and construction of a statute is an issue for

the court to decide.” Id. We do not defer to the agency’s interpretation of

its own statutory authority to issue a rule unless “the legislature has
                                      13

clearly vested that interpretation in the agency.” Id. This is consistent

with our Renda line of cases. See 784 N.W.2d at 13.

      For example, in Kopecky v. Iowa Racing & Gaming Commission, we

declined to defer to the agency’s interpretation of its own authority to issue

a rule allowing it consider the economic effect of a new gaming operation

on existing facilities because “we [were] not firmly convinced the legislature

vested the Commission with the authority to interpret our statutes when

it enacts its rules.” 891 N.W.2d 439, 442 (Iowa 2017).

      Similarly, we are not persuaded here that the legislature clearly

vested the IDOT with interpretive authority to determine its own authority.

None of the relevant statutes expressly give the IDOT interpretive

authority. Cf. Iowa Med. Soc’y v. Iowa Bd. of Nursing, 831 N.W.2d 826,

827, 829–30, 841 (Iowa 2013) (noting that Iowa Code section 147.76

expressly grants the nursing board interpretive authority and applying a

deferential standard in determining that the board had authority to issue

certain rules).

      As justification for the rules, the IDOT relies in part on general

provisions. See Iowa Code § 306.4(1) (providing that “[j]urisdiction and

control over the primary roads shall be vested in the department”); id.

§ 307.12(1)(j) (granting authority to “[a]dopt rules . . . as the director deems

necessary for the administration of the department and the exercise of the

director’s and department’s powers and duties”).            These provisions,

however, contain generic terms like “jurisdiction” and “deems necessary.”

Such terms are widely used in “other areas of law” besides transportation

and are not “specialized terms within the expertise of the agency.” Renda,

784 N.W.2d at 14.

      The IDOT also relies on its authority to eliminate “obstructions” from

highway rights-of-way as found in Iowa Code chapter 318.               But the
                                     14

legislature has provided its own definition of “obstruction.” Iowa Code

§§ 318.1(4), .3. This typically presents an “insurmountable obstacle” to

the conclusion that the IDOT has been vested with interpretive authority

over the term. See Iowa Dental Ass’n v. Iowa Ins. Div., 831 N.W.2d 138,

145 (Iowa 2013). On the contrary, “it indicates we ought to apply the

legislative definition ourselves.”   Id.   Accordingly, we must determine

ourselves whether the ATE rules are “[b]eyond the authority delegated to

the agency by any provision of law or in violation of any provision of law.”

Iowa Code § 17A.19(10)(b).

      In considering whether the agency followed proper rulemaking

procedure under Iowa Code section 17A.4, we apply the relevant standards

of section 17A.19(10). See Iowa Fed’n of Labor, AFL–CIO v. Iowa Dep’t of

Job Serv., 427 N.W.2d 443, 445 (Iowa 1988) (en banc) (applying section

17A.19(8), now section 17A.19(10)); see also Teleconnect Co. v. Iowa State

Commerce Comm’n, 404 N.W.2d 158, 162 (Iowa 1987) (same). The test is

one of substantial compliance with section 17A.4. Iowa Fed’n of Labor,

427 N.W.2d at 450; see Iowa Code § 17A.4(5).

      When the question is whether the agency erred in applying its rules,

“then the challenge is to the agency’s application of the law to the facts,

and the question on review is whether the agency abused its discretion by,

for example, employing wholly irrational reasoning or ignoring important

and relevant evidence.” Meyer v. IBP, Inc., 710 N.W.2d 213, 219 (Iowa

2006); see also Iowa Code § 17A.19(10)(l); Neal v. Annett Holdings, Inc., 814

N.W.2d 512, 518 (Iowa 2012).

      III. IDOT’s Authority to Promulgate the ATE Rules.

      The Cities first contend that the IDOT exceeded its statutory

authority in promulgating the ATE administrative rules. Although this is

framed as both a home rule argument and an argument that the IDOT
                                     15

went beyond its own statutory authority in issuing the rules, the

arguments are really one and the same.

      Within Iowa’s constitutional and statutory framework, the Cities

have retained certain rights, “except as expressly limited by the

Constitution of the State of Iowa, and if not inconsistent with the laws of

the general assembly.” See Iowa Code § 364.1 (emphasis added); see also

Iowa Const. art. III, § 38A (“Municipal home rule”).      Therefore, despite

home rule, state law, implemented through valid administrative rule, will

displace an otherwise valid municipal ordinance. See Iowa Code § 364.1;

see also Iowa Const. art. III, § 38A. However, invalid state administrative

rules cannot be enforced against a municipality. Cf. City of Coralville v.

Iowa Utils. Bd., 750 N.W.2d 523, 529 (Iowa 2008).         The issue thus is

whether the IDOT had the authority to promulgate the rules to begin with.

Since we conclude they do not have the authority to do so, such rules are

unenforceable against the Cities and there is no conflict between the rules

and the Cities’ ordinances.

      In City of Davenport v. Seymour, we addressed whether municipal

ordinances regarding ATE systems were preempted by state law (not state

administrative rules). 755 N.W.2d 533, 535 (Iowa 2008). We held that the

legislature had not preempted a Davenport ATE ordinance. Id. at 535–36.

That case did not involve a conflict with the IDOT, nor did it involve agency

action at all; the question was whether the ordinance conflicted with the

statutory provisions. Id. The statutes at issue in that case were the “traffic

regulation and enforcement provisions of Iowa Code chapter 321 (laws of

the road) and sections 364.22(5)(b) (municipal infractions), 805.6 (form of

citation in criminal cases), and 805.8A (schedule of criminal fines).” Id. at

537. This case presents a different question: a conflict between municipal

action and state administrative rules.
                                     16

       Ordinarily, state agency rules are given the “the force and effect of

law.” Stone Container Corp. v. Castle, 657 N.W.2d 485, 489 (Iowa 2003)

(quoting Greenwood Manor v. Iowa Dep’t of Pub. Health, 641 N.W.2d 823,

835 (Iowa 2002)). However, “agencies have ‘no inherent power and [have]

only such authority as [they are] conferred by statute or is necessarily

inferred from the power expressly given.’ ” Wallace v. Iowa State Bd. of

Educ., 770 N.W.2d 344, 348 (Iowa 2009) (alterations in original) (quoting

Zomer v. W. River Farms, Inc., 666 N.W.2d 130, 132 (Iowa 2003)). For a

rule to be validly adopted, it “must be within the scope of the powers

delegated to [the agency] by statute.” Id. (quoting Iowa Power & Light Co.

v. Iowa State Commerce Comm’n, 410 N.W.2d 236, 239 (Iowa 1987)). Thus,

if the rules adopted by the agency “exceed the agency’s statutory authority,

the rules are void and invalid.” Id. “An agency cannot by rule . . . expand

or limit authority granted by statute.” Smith–Porter v. Iowa Dep’t of Human

Servs., 590 N.W.2d 541, 545 (Iowa 1999).

       In deciding whether the ATE administrative rules promulgated by

the IDOT were validly adopted, we must determine whether their adoption

was within the scope of authority delegated to the IDOT by the legislature.

“We have declined to find legislative authorization for agency rulemaking

in the absence of a specific grant of authority.” Wallace, 770 N.W.2d at

348.   When the legislature has given an agency general rulemaking

authority but has also granted specific authority in particular areas, the

agency cannot then extend the specific grants beyond their scope.

       Our cases reflect this principle.   In Brakke, we found that the

specific legislative grant of authority to promulgate rules “for the

quarantine of diseased preserve whitetail” could not be used by the

department of natural resources (DNR) to promulgate rules allowing the

quarantine of (1) nondiseased deer that had also been exposed to the
                                    17

disease or (2) the land where the diseased deer had been. 897 N.W.2d at

531, 541–42 (quoting Iowa Code § 484C.12(1)).

             We therefore conclude that Iowa Code section 484C.12
      should be read according to its ordinary meaning. The
      consequence of this interpretation is that the agency lacked
      the statutory authority to promulgate the administrative rule
      expanding the scope of quarantines to include fencing of lands
      for a five-year period when all diseased preserve wildlife have
      been eradicated.      As a result, the agency was without
      authority to issue the emergency order in this case. If the
      legislature wishes to expand quarantine powers as suggested
      by the DNR rule, it is, of course, free to do so.

Id. (footnote omitted). We reached this conclusion even though “Iowa Code

chapter 484C generally grants DNR the authority to regulate preserve

whitetail.” Id. at 531; see Iowa Code § 484C.2(2) (“This chapter authorizes

the department of natural resources to regulate preserve whitetail.”).

      We applied similar reasoning in Wallace.       There, the plaintiffs

challenged a school district’s decision to close five elementary schools on

the ground the school district had failed to comply with rules promulgated

by the state board of education regarding school closure decisions. 770

N.W.2d at 346. The school district responded that the board of education

did not have the authority to promulgate those rules, rendering them
invalid. Id. The board had been authorized by statute to “[a]dopt rules

under chapter 17A for carrying out the responsibilities of the department.”

Id. at 348 (alteration in original) (quoting Iowa Code § 256.7(5) (2003)).

However, we found that this language did not grant the board “unlimited

power to regulate matters within the agency’s expertise.”        Id.     The

legislature had expressly authorized the board to adopt rules regarding

many other areas, but not school closures. Id. at 348–49. We concluded

that “the notable absence of a legislative grant to the [state board] of

authority to adopt rules regulating school closure decisions” meant that
                                     18

such power was not within the scope of its authority. Id. at 349. Therefore,

the rules were void. Id.

      Likewise, in Litterer v. Judge, we rejected an effort to force the

secretary of agriculture to adopt rules mandating ten percent ethanol

content in all motor vehicle fuel sold in Iowa. 644 N.W.2d 357, 359–60

(Iowa 2002). The secretary had refused to promulgate such a rule on the

basis that she lacked the legislative authority to do so. Id. at 360. The

statute at issue provided,

      The secretary shall adopt rules pursuant to chapter 17A for
      carrying out this chapter. The rules may include, but are not
      limited to, specifications relating to motor fuel or oxygenate
      octane enhancers. In the interest of uniformity, the secretary
      shall adopt by reference or otherwise specifications relating to
      tests and standards for motor fuel or oxygenate octane
      enhancers, established by the American society for testing
      and materials (A.S.T.M.), unless the secretary determines
      those specifications are inconsistent with this chapter or are
      not appropriate to the conditions which exist in this state.

Id. at 363 (emphasis omitted) (quoting Iowa Code § 214A.2(1) (1999)).

      In other words, Iowa law gave the secretary of agriculture authority

to adopt rules to carry out the motor vehicle fuel statutes, including the

express authority to promulgate rules relating to specifications for motor
fuel. Id. Nonetheless, we rejected the plaintiffs’ appeal because there was

“no specific grant of authority by the legislature in section 214A.2

permitting the secretary to regulate the content level of ethanol in motor

fuel.” Id. In our examination of the legislative history and the meaning of

other terms in the statute, we did not find evidence of legislative intent to

bestow this authority. See id. at 363–65. Therefore, despite the existence

of a closely related grant of authority, we decided the statute did not confer

authority to promulgate rules mandating ethanol content. See id. at 365.
                                     19

      In another case, we found that the DNR lacked statutory authority

to issue an administrative order pertaining to the cleanup of solid waste.

First Iowa State Bank v. Iowa Dep’t of Nat. Res., 502 N.W.2d 164, 168 (Iowa

1993). The DNR had determined that a bank foreclosing on property was

responsible for the cost of cleanup of illegally dumped solid waste on the

site. Id. at 165. We acknowledged that “[s]pecific statutory authority for

adopting administrative rules relating to solid waste is provided in section

455B.304.” Id. at 168. However, we also noted that “no reference is made

to adoption of rules relating to cleanup of open dumps.” Id. Additionally,

Iowa law imposed liability “for cleanup of a hazardous condition . . . upon

a person having control over the hazardous substance.” Id.

      Given these statutory provisions, we reasoned that the DNR lacked

the necessary authority. Id. Interpreting the statute to provide the agency

with authority to issue the administrative order would have imposed

broader liability for cleanup of solid waste than for cleanup of hazardous

waste—contrary to the underlying statutory scheme. See id. We agreed

with the district court that “the action of the DNR is in excess of the

statutory authority granted to it.” Id.

      Barker v. Iowa Department of Transportation also found that the

department of transportation had exceeded its rulemaking authority. 431

N.W.2d 348 (Iowa 1988). There, the department revoked a driver’s license

on the basis of a breath test that had indicated a blood alcohol content of

.108%. Id. at 348–49. The legal challenge concerned department rules

that had established the margin of error for a blood test at plus or minus

five percent. Id. at 349. The underlying statute referenced an “established

margin of error” but neither designated that margin nor expressly

authorized the department to make the designation.        Id. (quoting Iowa

Code § 321J.12 (1987)).       Because the administrative rules review
                                     20

committee challenged the rule, the burden was on the agency to establish

its authority to promulgate the rule. Id. The department pointed to its

general statutory authority to promulgate administrative rules to carry out

any laws whose enforcement was vested in the department. Id. at 350.

However, we found that the department lacked the authority to establish

a standard for what would constitute a violation, as such a power must be

expressly given. Id. (“Authority for such a power cannot be implied . . . .”).

The authority to approve devices could not be broadly interpreted as

including authority to promulgate a rule “establishing a margin of error for

the devices it has approved.” Id.

      In another case, several public utility companies challenged the

state commerce commission’s authority to promulgate a rule requiring

utility financing of energy conservation measures. Iowa–Ill. Gas & Elec.

Co. v. Iowa State Commerce Comm’n, 334 N.W.2d 748, 749 (Iowa 1983).

There, we found that even the express statutory mandate that “[t]he

commission shall promulgate rules concerning the use of energy

conservation strategies by rate or service regulated gas and electric

utilities” was not sufficient to confer authority to promulgate rules

requiring utility financing of conservation measures. Id. at 752 (quoting

Iowa Code § 476.2 (1981)). “Such commission authority, if it exists, must

be implied from the statutory language the commission relies on.” Id.

Using the ordinary meaning of the statutes, we concluded that the phrases

“programs designed to promote” and “rules concerning the use of” meant

the commission had the authority “to encourage, influence, and provide

incentives relating to energy conservation.” Id. However, that still was not

enough to give the authority to require utility financing of energy

conservation, undeniably a method of achieving energy conservation. Id.

We found that the Code provisions “relied on by the commission do not
                                     21

mention financing at all, let alone permit it.” Id. at 753. Therefore, the

commission did not have the authority to promulgate rules requiring

utility financing. Id. Because the authority to require financing was a

“departure from traditional utilities regulation,” we concluded “that it must

be clearly manifested by legislative enactment.” Id. at 754.

      In Marquart v. Maucker, an employee of a state university

successfully contested an administrative rule that had resulted in

withholding from her final paycheck. 215 N.W.2d 278, 279 (Iowa 1974).

The university had established various rules and regulations for the use

of its parking lots, enforceable by fines that could be deducted from an

employee’s paycheck. Id. The university put forth several statutes that it

claimed as the basis of its authority, including the authority to set speed

limits, but we found that these statutes could not imply the authority to

adopt the parking regulations in question. See id. at 282.

      The foregoing cases follow a pattern. In Brakke, Wallace, Litterer,

First Iowa State Bank, Barker, Iowa–Illinois Gas & Electric, and Marquart,

the legislature gave the agency authority to issue rules in a specific area,

but not the specific area at issue.       Accordingly, we found that an

overarching general grant of authority was an insu

      fficient basis for rulemaking in that area.

      Even when we have upheld the agency’s authority to promulgate

rules, we first determined that the legislature had expressly granted

statutory authority to promulgate rules related to the subject area. For

example, in Meredith Outdoor Advertising, Inc., we found that the IDOT

could promulgate rules requiring the revocation of permits when billboard

sign owners reconstructed or modified nonconforming signs more than

660 feet from an interstate without seeking a new permit. 648 N.W.2d at

116–17. There, the plaintiff appealed a decision by the IDOT revoking two
                                    22

permits for outdoor advertising signs after the signs were reconstructed or

modified without the plaintiff having obtained new permits. Id. at 112.

This was in violation of the IDOT’s administrative rule. Id. The plaintiff

contended that the rule exceeded the IDOT’s rulemaking authority,

pointing to the fact that a different chapter, 306B, specifically granted

authority to the department to “promulgate and enforce rules . . .

governing the erection, maintenance, and frequency of advertising devices

within six hundred sixty feet of the edge of the right of way.” Id. at 116

(omission in original) (quoting Iowa Code § 306B.3 (1999)). Nevertheless,

we found that “several other statutory sections inherently provide the

department with sufficient authority to enact regulations controlling the

maintenance of nonconforming signs.” Id. at 117. We concluded that “the

legislature intended to provide the department with the power to fill in any

gaps within chapter 306C by enacting administrative rules.” Id.

      We noted in Meredith Outdoor Advertising that Iowa Code section

306C.12 generally prohibited the signs in question.            Id. at 115.

Additionally, “[s]ections 306C.18(3) and 306C.19 require sign owners such

as [the plaintiff] to follow department rules or be subject to removal.” Id.

at 117. Furthermore, “[a]dditional sections provide general authority to

the department to adopt such rules deemed necessary to carry out its

duties.” Id. Based on this combination of authority, we found the rule

was within the IDOT’s delegated authority. See id.

      In Overton v. State, a prison inmate challenged the authority of the

Iowa Department of Corrections to make rules requiring him to reimburse

a staff member for eyeglasses broken during an altercation. 493 N.W.2d

857, 858 (Iowa 1992).     The contested rule permitted the sanction of

“assessed costs” when an inmate violated a disciplinary rule. Id. at 859.

Iowa law provided, “Inmates who disobey the disciplinary rules of the
                                      23

institutions to which they are committed shall be punished by the

imposition of the penalties prescribed in the disciplinary rules. . . .” Id.

(omission in original) (quoting Iowa Code § 246.505(1)). We found that the

department had the necessary authority because the assessed costs

constituted a penalty. Id.

      In Frank v. Iowa Department of Transportation, we were charged with

deciding “whether the department was within its statutory authority to

conclude under its rules that a moving traffic-law violation includes failing

to have a valid chauffeur’s license.” 386 N.W.2d 86, 88 (Iowa 1986). We

determined that it was, particularly noting the statutory basis for the

authority to promulgate such rules:

             Section 321.210 authorizes the department to establish
      rules for license suspension if the operator is found to be a
      habitual violator, and provides only three exclusions for
      violations of statutory or municipal ordinances in determining
      whether or not to suspend a license. Pursuant to this section,
      the department defines a “habitual violator” as one who has
      convictions for more than two moving traffic-law violations
      within twelve months. It then defines “moving traffic law
      violation” as “any traffic law violation except” ones regarding
      equipment, parking, registration laws, expired licenses or
      permits, failures to appear, weights and measures, and
      disturbing the peace. There are no exceptions for failing to
      have a valid chauffeur’s license.

Id. (citations omitted). We pointed out that “the legislature itself did not

see fit to include . . . the failure to have a valid chauffeur’s license in its

exemptions in section 321.210.” Id. We concluded that the department

“may properly consider the failure to have a valid chauffeur’s license to be

a moving traffic-law violation under its rules.” See id.

      In Milholin, we “decide[d] the validity and effect of a rule of the Iowa

Real Estate Commission requiring all real estate listing agreements to be

in a writing containing all essential terms.”     320 N.W.2d at 553.       The

district court had found the rule to be invalid. Id. We reversed, deciding
                                     24

that the rule was a valid exercise of the commission’s authority. Id. The

relevant chapter vested the commission “with far-reaching authority to

license, regulate and discipline brokers and salespersons.” Id. at 554. The

commission also had express, general rulemaking authority. Id. Although

the statute did not grant the specific authority to promulgate rules on this

subject, the rule was nevertheless a regulatory measure over brokers and

salespersons, thus allowing the commission to reasonably conclude that

promulgating this rule fell within its statutory authority. See id.

      In Temple v. Vermeer Manufacturing Co., we concluded that a rule

promulgated by the industrial commissioner was within its specific

statutory authority. 285 N.W.2d 157, 159–60 (Iowa 1979). The rule at

issue there required the commissioner “to decide an appeal on the record

established before the deputy commissioner unless the commissioner is

satisfied that additional evidence is material and that there was good

reason for failure to present the additional evidence to the deputy

commissioner.” Id. at 159. We concluded that the rule was “well within

the legislative authorization.” Id. There, the statute provided, “In addition

to the provisions of section 17A.15, the industrial commissioner, on

appeal, may limit the presentation of evidence as provided by rule.” Id.

(quoting Iowa Code § 86.24 (1979)). We noted that section 86.24 was a

“particular statutory basis for the rule,” and thus the rule was within the

commissioner’s authority. Id. at 160.

      Meredith Outdoor Advertising, Overton, Frank, and Temple fall into

the pattern we have already noted. In those cases, legislation gave the

agency specific authority to decide when billboards could be permitted that

were visible from an interstate highway (although more than 660 feet away

from the highway), impose penalties, define a moving violation, and limit

evidence. Thus, in each of those cases, the agency rule was upheld. As
                                            25

noted, the trend of the above cases is that when the statute has granted

general rulemaking authority and followed it up with specific authority

over particular areas, the agency is not free to interpret the general

rulemaking authority as granting unlimited rulemaking authority. Neither

may the agency interpret the specific grants of authority broadly so as to

encompass areas not clearly included within those grants.

       Milholin is, perhaps, more difficult to reconcile with the rest of the

caselaw. The real estate commission had been given authority over the

licensing, regulation, and disciplining of brokers and salespersons. 320

N.W.2d at 554. We concluded that a rule requiring listing agreements to

be in writing was a rational way to “regulat[e] broker conduct to protect

the public.” Id. Milholin was decided thirty-six years ago and should be

read along with more recent decisions. 3

       We turn now to the IDOT’s asserted basis for authority here. The

IDOT points to its specific statutory authority to remove “obstructions”

from the highway right-of-way of the primary highway system. See Iowa

Code §§ 318.4, .7 (2013). However, an “obstruction”

       means an obstacle in the highway right-of-way or an
       impediment or hindrance which impedes, opposes, or
       interferes with free passage along the highway right-of-way,
       not including utility structures installed in accordance with
       an approved permit.

Id. § 318.1(4). The legislation continues,




       3Notably,   a dissenting opinion urged,
               The subject of the form or contents of contracts between realtors
       and listers does not come within the scope of the chapter. We are already
       inundated by a proliferation of agency rules. I do not think we should
       enlarge agencies’ rule-making powers additionally by construing statutes
       beyond what appears to be legislative intent in those statutes.
Milholin, 320 N.W.2d at 556 (Uhlenhopp, J., dissenting).
                                    26

            A person shall not place, or cause to be placed, an
      obstruction within any highway right-of-way. This prohibition
      includes, but is not limited to, the following actions:

            1. The excavation, filling, or making of any physical
      changes to any part of the highway right-of-way, except as
      provided under section 318.8.

           2. The cultivation or growing of crops within the
      highway right-of-way.

             3. The destruction of plants placed within the highway
      right-of-way.

             4. The placing of fences or ditches within the highway
      right-of-way.

             5. The alteration of ditches, water breaks, or drainage
      tiles within the highway right-of-way.

           6. The placement of trash, litter, debris, waste material,
      manure, rocks, crops or crop residue, brush, vehicles,
      machinery, or other items within the highway right-of-way.

            7. The placement of billboards, signs, or advertising
      devices within the highway right-of-way.

            8. The placement of any red reflector, or any object or
      other device which shall cause the effect of a red reflector on
      the highway right-of-way which is visible to passing motorists.

Id. § 318.3.

      The list of potential obstructions in Iowa Code section 318.3 does

not include ATE equipment, nor does it include anything comparable to

ATE equipment. Id. § 318.3. The first seven items consist of physical

obstacles within the right-of-way. Id. § 318.3(1)–(7). The last item, a “red

reflector,” is presumably included because a red reflector is a recognized

warning device for motorists. See id. § 321.389 (requiring a red reflector

on the rear of all vehicles). Therefore, a red reflector that wasn’t warning
                                            27

about a vehicle or other hazard could throw motorists off the track and

itself pose a danger. 4

       Significantly, Iowa Code chapter 318 requires every “obstruction” to

be removed and provides that any person who places an “obstruction” in

a highway right-of-way is deemed to have created a public nuisance. See

id. §§ 318.5(1)–(2), .6(1) (2013).          So if the IDOT’s interpretation were

correct, the Cities would be creating a public nuisance.                        Also, the

prohibition only applies to obstructions “within any highway right-of-way.”

Id. § 318.3. Notably, all the interstate ATE systems at issue in this case

were mounted on existing overhead truss signs. 5

       Reading chapter 318 as a whole, it is not plausible to use the term

“obstruction” for a traffic camera that takes a photograph for law

enforcement purposes of a vehicle going more than ten miles over the

speed limit. 6

       The IDOT also relies on two broadly worded statutes: Iowa Code

sections 307.2 and 307.12(1)(j). The former states that the IDOT “shall be

responsible for the planning, development, regulation and improvement of


       4Chapter 318 was enacted in 2006. 2006 Iowa Acts ch. 1097. Its predecessor,

chapter 319, contained a provision that served a similar purpose:
               Except for official traffic-control devices as defined by section
       321.1, subsection 46, no person shall place, erect, or attach any red
       reflector, or any object or other device which shall cause a red reflectorized
       effect, within the boundary lines of the public highways so as to be visible
       to passing motorists.
Iowa Code § 319.12 (2005).
       5Inseveral instances, the IDOT gave the Cities the option of disabling, rather than
removing, the ATE equipment. If the equipment were really an “obstruction” within the
meaning of chapter 318, disabling would not be a remedy.
       6Similarly,    we do not believe that the IDOT had authority to promulgate the rules
under Iowa Code section 321.348, which makes it “unlawful for any city to close or
obstruct any street or highway which is used as the extension of a primary road within
such city . . . .” Iowa Code § 321.348. Whatever their merits or demerits, the ATE systems
are not an “obstruction.”
                                          28

transportation in the state as provided by law.”              Id. § 307.2.     Section

307.12(1)(j) authorizes the director of the department to “[a]dopt rules in

accordance with chapter 17A as the director deems necessary for the

administration of the department and the exercise of the director’s and

department’s powers and duties.” Id. § 307.12(1)(j).

       The IDOT argues that these general provisions sustain the ATE

rules. However, neither of these two provisions broadens the reach of the

IDOT; rather, each incorporates and relies upon other legal sources. Iowa

Code section 307.2 states that the IDOT is responsible for the regulation

of transportation “as provided by law.” Section 307.12 empowers the IDOT

to adopt rules to exercise its “powers and duties.” In other words, the

IDOT can adopt rules, but they have to be in furtherance of legal authority

that the agency otherwise possesses.

       The IDOT’s argument runs contrary to our prior holdings in Wallace,

Litterer, Iowa–Illinois Gas & Electric, Barker, Brakke, and First Iowa State

Bank. For example, in Wallace we said, “[G]eneral authorization of this

type does not grant to an administrative agency unlimited power to

regulate matters within the agency’s expertise.”              770 N.W.2d at 348.

Furthermore, the delegation of authority to the IDOT over other specific

areas prevents the IDOT from claiming specific authority here. 7

       The other statutes cited by the IDOT as authority for promulgating

the ATE rules are similarly generic and not specific to ATE systems. Iowa

Code section 306.4(1) states that “[j]urisdiction and control over the


       7Our   decision in Lenning v. Iowa Department of Transportation provides a useful
contrast to the present case. 368 N.W.2d 98 (Iowa 1985). There we upheld an IDOT rule
that made persons with prior license revocations based upon OWI convictions ineligible
for work permits during the period of a subsequent revocation. Id. at 100. Although we
quoted the IDOT’s general rulemaking authority in a footnote, we sustained the rule
because the underlying statute specifically gave the IDOT discretion on whether to issue
temporary restricted licenses in these circumstances. Id. at 101–02 & n.1.
                                    29

primary roads shall be vested in the department.” Iowa Code § 306.4(1).

Section 306.4(4)(a) provides,

      Jurisdiction and control over the municipal street system
      shall be vested in the governing bodies of each municipality;
      except that the department and the municipal governing body
      shall exercise concurrent jurisdiction over the municipal
      extensions of primary roads in all municipalities. When
      concurrent jurisdiction is exercised, the department shall
      consult with the municipal governing body as to the kind and
      type of construction, reconstruction, repair, and maintenance
      and the two parties shall enter into agreements with each
      other as to the division of costs thereof.

Id. § 306.4(4)(a). The IDOT argues that “[s]ections 306.4(1) and 306.4(4)(a)

should be read together and harmonized with the DOT having final

authority to adopt the subject ATE rules.”

      We are not persuaded.      We think that the ordinary meaning of

“jurisdiction and control over the primary roads” in this context means

that the department has authority over the establishment, alteration, and

vacation of such roads.    Those are the subjects covered by Iowa Code

chapter 306. See City of Cedar Rapids v. State, 478 N.W.2d 602, 605 (Iowa

1991) (“We believe that the intent and purpose of [section 306.4(3) (now

306.4(4))] is to establish the jurisdiction and control of municipalities in
the establishment, alteration, and vacation of roadways within the

municipal limits.”).

      The IDOT’s argument proves too much. Suppose the Cities decided

to station numerous patrol cars on Interstates 380 and 235 and Highway

61 to catch and ticket speeders. Could the IDOT issue a rule banning the

practice on the ground that it has “jurisdiction and control” over these

roads? Clearly not.

      Furthermore, Iowa Code section 321.285(5) gives the IDOT authority

to establish speed limits under circumstances on “fully controlled-access
                                     30

. . . highways.” See Iowa Code § 321.285(5). But missing from this specific

grant is any authority over methods of enforcing speed limits. See Litterer,

644 N.W.2d at 365.

      Brakke is instructive here, because it is in many ways analogous to

the present case. 897 N.W.2d 522. Like the IDOT, the DNR possesses

broad authority over its domain. Section 455A.2 states, “A department of

natural resources is created, which has the primary responsibility for state

parks and forests, protecting the environment, and managing fish, wildlife,

and land and water resources in the state.”           Iowa Code § 455A.2.

Furthermore, Iowa Code section 484C.2(2) “authorizes the department of

natural resources to regulate preserve whitetail,” and the DNR is imbued

with a statutory authority to “adopt rules pursuant to chapter 17A as

necessary to administer” the chapter regarding whitetail deer.             Id.

§ 484C.3.

      Nonetheless, in Brakke, we found that the DNR could not

promulgate quarantine rules outside the particular scope of section

484C.12, even though those rules might appear otherwise consistent with

the broad rulemaking authority and legislative intent to protect whitetail

deer. 897 N.W.2d at 533–34. We noted the department’s argument that

the clear legislative intent was to eradicate the particular disease at issue,

since it was mentioned by name by the legislature. Id. at 532 (“According

to the DNR, it would make no sense for a legislature so concerned with

[this disease] to deny the state regulatory authorities the ability to protect

the whitetail population from a primary pathway for transmission of the

disease, namely exposure to prion-contaminated land.”). The expanded

quarantine was certainly consistent with that goal.       See id.   Still, the

rulemaking authority given to the department did not extend beyond the

type of quarantine referred to in Iowa Code section 484C.12(1). Id. at 541.
                                           31

       Likewise, here, the IDOT’s general mission to preserve motorist

safety is not enough to allow it to deviate from its specific statutory

authority, by treating an ATE system as a right-of-way obstruction. As we

said in Brakke, if the legislature wants to expand the IDOT’s powers to

include regulation of ATE systems, “it is, of course, free to do so.” Id. at

541–42.

       Other state legislatures have expressly vested state agencies with

authority over ATE systems.            See, e.g., Ariz. Rev. Stat. Ann. § 28–641

(Westlaw through 2d Reg. Sess. 2018) (giving the department of

transportation the authority to “adopt a manual and specifications for a

uniform system of control devices,” including photo enforcement systems);

625 Ill. Comp. Stat. Ann. 7/10 (West, Westlaw through P.A. 100–585 of

2018 Reg. Sess.) (granting the department of state police the authority to

establish ATE systems); Md. Code. Ann., Transp. § 25-104 (West, Westlaw

through 2018 Reg. Sess.) (“The State Highway Administration shall adopt

a manual and specifications for a uniform system of traffic control

devices,” including automatic speed monitoring systems). To date, our

general assembly has not pursued this course of action. 8

       The IDOT contends that by not enacting legislation to overturn the

ATE rules, the legislature has impliedly endorsed them. The IDOT cites

State v. Miner, where we said,

       The Iowa Administrative [P]rocedure Act affords the legislature
       an opportunity to object to agency rules and to override them
       by statute. These steps were not taken by the legislature;
       therefore, we assume that the legislature approved of the

       8As  noted, the legislature has specifically empowered the IDOT to act in other
areas, but not with respect to ATE systems. We have long recognized the principle of
expressio unius est exclusio alterius, i.e., the expression of one is the exclusion of the
other, as an aid to statutory interpretation. See, e.g., Staff Mgmt. v. Jiminez, 839 N.W.2d
640, 649 (Iowa 2013); Thomas v. Gavin, 838 N.W.2d 518, 524 (Iowa 2013); Kucera v.
Baldazo, 745 N.W.2d 481, 487 (Iowa 2008).
                                      32

      requirement that brokers be licensed as dealers and of the
      resulting application of the title requirements to all who
      initiate the retail sale of motor vehicles.

331 N.W.2d 683, 687 (Iowa 1983) (citation omitted). However, Miner is

distinguishable. Miner involved a specific grant of legislative authority to

adopt the rule at issue. Id. at 686. We found that the administrative rule

“was only verbalizing what section 322.3(2) had already directed.” Id. The

administrative rule, in other words, “was following what the legislature had

already directed in section 322.3(2).” Id. at 687. Here, the rule lacks such

support.    We are unwilling to adopt a principle that whenever the

legislature declines to pass legislation overturning a rule, it has statutorily

authorized that rule.    This flips article III and article IV of the Iowa

Constitution.

      In 2014, the general assembly enacted a statutory ban on the use of

drones for traffic law enforcement.     See 2014 Iowa Acts ch. 1111, § 1

(codified at Iowa Code § 321.492B) (2015). This shows that the legislature

has the ability to enact laws regulating newer methods of traffic law

enforcement.

      Therefore, we conclude that the IDOT did not have statutory

authority to promulgate the administrative rules dictating placement and

continued use of ATE equipment by the Cities. As a result, the agency was

without authority to rely on those rules to order the Cities to move, remove,

or disable their ATE systems.
      Because of our determination that the IDOT lacked authority to

issue the ATE rules, we need not reach the Cities’ additional arguments

that the IDOT failed to comply with proper rulemaking procedure in

adopting the 1000-foot rule, or that the ATE rules and their application to

the Cities were illogical and wholly irrational, failed to address relevant

and important information that a rational decision-maker would consider,
                                    33

and were otherwise arbitrary and capricious. See Iowa Code § 17A.4(1)(a);

id. § 17A.19(10)(i), (j), (n).

       IV. Conclusion.

       We conclude that the IDOT was without statutory authority to

promulgate its administrative rules regarding the municipalities’ ATE

systems.    We reverse the district court’s order and remand for further

proceedings consistent with this opinion.

       REVERSED AND REMANDED.

       All justices concur except Hecht, J., who takes no part.
