FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

ALLIED CONCRETE AND SUPPLY

CO., a California corporation;

CALPORTLAND COMPANY, a

California Corporation; GARY

BALE REDI-MIX CONCRETE, INC., a

California corporation; HOLLIDAY

ROCK CO., INC., a California

corporation; NATIONAL READY

MIXED CONCRETE CO., a

California corporation;

ROBERTSON’S READY MIX, LTD., a

California limited partnership;

SPRAGUES ROCK AND SAND

COMPANY, a California

corporation; SUPERIOR READY MIX

CONCRETE L.P.,

Plaintiffs-Appellees,

v.

CHRISTINE BAKER, in her official

capacity as the Director of the

Department of Industrial Relations

of the State of California; JULIE A.

SU, in her official capacity as

Labor Commissioner of the State

of California, Division of Labor

Standards Enforcement,

Defendants,

No. 16-56546

D.C. No.

CV 16-4830 RGK
2 ALLIED CONCRETE AND SUPPLY V. IBT

INTERNATIONAL BROTHERHOOD OF

TEAMSTERS,

Intervenor-Defendant-Appellant.

ALLIED CONCRETE AND SUPPLY

CO., a California corporation;

CALPORTLAND COMPANY, a

California Corporation; GARY

BALE REDI-MIX CONCRETE, INC., a

California corporation; HOLLIDAY

ROCK CO., INC., a California

corporation; NATIONAL READY

MIXED CONCRETE CO., a

California corporation;

ROBERTSON’S READY MIX, LTD., a

California limited partnership;

SPRAGUES ROCK AND SAND

COMPANY, a California

corporation; SUPERIOR READY MIX

CONCRETE L.P.,

Plaintiffs-Appellees,

v.

CHRISTINE BAKER, in her official

capacity as the Director of the

Department of Industrial Relations

of the State of California; JULIE A.

SU, in her official capacity as

Labor Commissioner of the State

of California, Division of Labor

Standards Enforcement,

Defendants-Appellants.

No. 17-55343

D.C. No.

CV 16-4830 RGK
ALLIED CONCRETE AND SUPPLY V. IBT 3

ALLIED CONCRETE AND SUPPLY

CO., a California corporation;

CALPORTLAND COMPANY, a

California Corporation; GARY

BALE REDI-MIX CONCRETE, INC., a

California corporation; HOLLIDAY

ROCK CO., INC., a California

corporation; NATIONAL READY

MIXED CONCRETE CO., a

California corporation;

ROBERTSON’S READY MIX, LTD., a

California limited partnership;

SPRAGUES ROCK AND SAND

COMPANY, a California

corporation; SUPERIOR READY MIX

CONCRETE L.P.,

Plaintiffs-Appellants,

v.

CHRISTINE BAKER, in her official

capacity as the Director of the

Department of Industrial Relations

of the State of California; JULIE A.

SU, in her official capacity as

Labor Commissioner of the State

of California, Division of Labor

Standards Enforcement,

Defendants-Appellees.

No. 17-55503

D.C. No.

CV 16-4830 RGK

OPINION
4 ALLIED CONCRETE AND SUPPLY V. IBT

Appeals from the United States District Court

for the Central District of California

R. Gary Klausner, District Judge, Presiding

Argued and Submitted March 7, 2018

Pasadena, California

Filed September 20, 2018

Before: A. Wallace Tashima, Richard A. Paez,

and Jacqueline H. Nguyen, Circuit Judges.

Opinion by Judge Tashima

SUMMARY*

Labor Law

The panel affirmed in part and reversed in part the district

court’s judgment and remanded in an action brought by a

group of ready-mix concrete suppliers, challengingCalifornia

Labor Code § 1720.9, which amended California’s prevailing

wage laws to include delivery drivers of ready-mix concrete.

The district court denied a motion of the International

Brotherhood of Teamsters (“IBT”) to intervene on the side of

the State to defend the law, and it granted the State’s motion

to dismiss plaintiffs’ claim that § 1720.9 was preempted by

the Federal Aviation Administration Authorization Act. The

* This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.
ALLIED CONCRETE AND SUPPLY V. IBT 5

district court granted summary judgment in favor of plaintiffs

on their claim that § 1720.9 violated the Equal Protection

Clause of the Fourteenth Amendment, ruling that, under the

rational basis test, there were no legally relevant differences

between ready-mix drivers and other delivery drivers;

therefore, the State did not have any legitimate justification

for singling out the ready-mix suppliers.

Reversing the district court’s grant of summary judgment

in favor of plaintiffs on their equal protection claim, the panel

concluded that the district court wrongly disregarded as

irrelevant certain differences between ready-mix drivers and

other drivers that the legislature could have relied on in

extending the prevailing wage law. The panel explained that

the California Supreme Court has stated that prevailing wage

laws further goals such as: (1) generally protecting

employees on public works projects, (2) benefitting the public

through the superior efficiency of well-paid employees, and

(3) permitting union contractors to compete with nonunion

contractors. The panel held that the legislature could have

rationally concluded that extending the prevailing wage law

to ready-mix drivers ahead of other drivers would further

these respective goals because ready-mix drivers: (1) are

more integrated into the construction process than other

materials drivers and should be paid accordingly; (2) are

more skilled than other drivers and provide a material that is

more important to public works projects than other materials

such that paying the prevailing wage will attract superior

drivers and improve public works; and (3) are more likely to

be unionized and, therefore, vulnerable to underbidding.

Reversing the district court’s denial of IBT’s motion to

intervene, the panel held that the union had a significantly

protectable interest at stake in the case. The panel concluded
6 ALLIED CONCRETE AND SUPPLY V. IBT

that IBT’s appeal was not moot in light of the reversal on the

equal protection claim.

The panel affirmed the district court’s dismissal of

plaintiffs’ claim of FAAAA preemption because the

prevailing wage law was not related to prices, routes, and

services within the meaning of the FAAAA’s preemption

clause.

COUNSEL

Ken Lau (argued), Assistant Chief Counsel; Christopher

Jagard, Chief Counsel; Office of the Director—Legal Unit,

Department of Industrial Relations, Oakland, California;

John J. Korbol and Mi Kim, Counsel, Office of the

Director—Legal Unit, Department of Industrial Relations,

Los Angeles, California; for Defendants-Appellants/CrossAppellees.

Michael G. Yoder (argued) and Christopher S. Whittaker,

O’Melveny& Myers LLP, Newport Beach, California; Anton

Metlitsky, O’Melveny & Myers LLP, New York, New York;

for Plaintiffs-Appellees/Cross-Appellants.

Scott A. Kronland (argued), Stacey M. Leyton, and Eric P.

Brown, Altshuler Berzon LLP, San Francisco, California, for

Intervenor-Defendant-Appellant/Amicus Curiae.

Kerry Shapiro, Jon Wilner, and Matthew J. Sanders, Jeffer

Mangels Butler & Mitchell LLP, San Francisco, California,

for Amicus Curiae California Construction and Industrial

Materials Association.
ALLIED CONCRETE AND SUPPLY V. IBT 7

OPINION

TASHIMA, Circuit Judge:

California’s general prevailing wage laws ensure that

workers employed on public works projects are paid a

minimum wage. In 2015, California amended the prevailing

wage laws to include delivery drivers of ready-mix concrete. 

Cal. Lab. Code § 1720.9.

A group of ready-mix concrete suppliers (collectively,

“Plaintiffs”) challenged § 1720.9, alleging that it violated the

Equal Protection Clause of the Fourteenth Amendment to the

United States Constitution (“equal protection claim”) and that

the Federal Aviation Administration Authorization Act of

1994 (“FAAAA”) preempted the state law. The International

Brotherhood of Teamsters (“IBT”) moved to intervene on the

side of the State to defend the law.

The district court denied IBT’s motion to intervene and

granted the State’s motion to dismiss Plaintiffs’ FAAAA

preemption claim. However, the district court granted

Plaintiffs’ summary judgment motion on the equal protection

claim, concluding that § 1720.9 did not pass muster under the

rational basis test. The court reasoned that there were no

legally relevant differences between ready-mix drivers and

other delivery drivers; therefore, the State did not have any

legitimate justification for singling out the ready-mix

suppliers.

We conclude that the district court wrongly disregarded

as irrelevant certain differences between ready-mix drivers

and other drivers that the legislature could have relied on in

extending the prevailing wage law. We thus reverse the
8 ALLIED CONCRETE AND SUPPLY V. IBT

district court’s grant of summary judgment in favor of

Plaintiffs and order the court to enter judgment on behalf of

Defendants. Likewise, we hold that IBT had a significantly

protectable interest at stake in the case and we reverse the

district court’s denial of IBT’s motion for leave to intervene. 

On the FAAAA preemption question, we affirm the district

court’s dismissal of Plaintiffs’ claim.

BACKGROUND

1. Prevailing Wage Laws and California Labor Code

§ 1720.9

California’s prevailingwage lawestablishesthe minimum

wage that workers employed on “public works” must receive. 

See Cal. Lab. Code §§ 1720, 1771. “Public works” is

generally defined as construction or related work, done under

contract, and paid for in any part out of public funds. Id.

§ 1720(a)(1). The California Supreme Court has described

the purpose of the general prevailing wage law:

The overall purpose of the prevailing wage

law . . . is to benefit and protect employees on

public works projects. This general objective

subsumes within it a number of specific goals:

to protect employees from substandard wages

that might be paid if contractors could recruit

labor from distant cheap-labor areas; to permit

union contractors to compete with nonunion

contractors; to benefit the public through the

superior efficiency of well-paid employees;

and to compensate nonpublic employees with

higher wages for the absence of job security
ALLIED CONCRETE AND SUPPLY V. IBT 9

and employment benefits enjoyed by public

employees.

Lusardi Constr. Co. v. Aubry, 824 P.2d 643, 649 (Cal. 1992).

The California Director of Industrial Relations (the

“Director”) publishes the prevailing wage rates and enforces

the law by collecting payroll (and other related) records from

employers. Cal. Lab. Code §§ 1771.4, 1776. Further, when

there is a question about the applicability of the prevailing

wage law, the Director determines “whether a specific project

or type of work is a public work.” Id. at § 1773.5(b); see also

id. § 1773(c) (establishing administrative appeal process). 

When there is a dispute, courts may also review whether a

worker is entitled to prevailing wages. See, e.g., Williams v.

SnSands Corp., 67 Cal. Rptr. 3d 606 (Ct. App. 2007); O.G.

Sansone Co. v. Dep’t of Transp., 127 Cal. Rptr. 799 (Ct. App.

1976). Courts and the Director both ask whether the worker’s

task was “functionally related to the process of construction,”

and “an integrated aspect of the ‘flow’ process of

construction.” O.G. Sansone, 127 Cal. Rptr. at 804; see also

A&A Ready Mix Concrete, Public Works Case No. 99-037

(Dep’t of Indus. Relations Apr. 10, 2000).

On October 10, 2015, Governor Edmund G. Brown, Jr.,

signed AB 219, which amended California’s prevailing wage

law by adding Labor Code §1720.9. It provides that “public

works” include “the hauling and delivery of ready-mixed

concrete to carry out a public works contract” regardless of

who employs the driver or whether the driver is delivering

from a dedicated batch plant. Cal. Lab. Code § 1720.9. 

Therefore, all ready-mix drivers delivering to public works

must be paid prevailing wages. Before adopting the final bill,

the California Legislature considered a version of AB 219
10 ALLIED CONCRETE AND SUPPLY V. IBT

that would have required payment of prevailing wages to

asphalt delivery drivers as well, but ultimately limited the

expansion to ready-mix concrete drivers.

Ready-mix concrete is defined as “concrete that is

manufactured in a factory or a batching plant, according to a

set recipe, and then delivered in a liquefied state by mixer

truck for immediate incorporation into a project.” Id.

§ 1720.9(b). Its ingredients are prepared and mixed at a

concrete plant. Production of concrete is time-sensitive

because concrete begins to set quickly after water is added. 

Ready-mix is delivered in specialized trucks with a rotating

tank. Id. Drivers of ready-mix trucks control the amount of

water added to the rotating tank and the speed at which the

tank spins, meaning that they can alter the nature of the

concrete.1 By contrast, even though asphalt deliverymay also

be time-sensitive, drivers transport asphalt in dump trucks,

rather than mixing trucks, and drivers cannot alter the asphalt

once it is in the truck. For certain projects, such as paving

roads, asphalt and ready-mix are interchangeable, for others,

such as building walls and other structural supports, the

materials are not substitutes.

2. Procedural Background

On June 30, 2016, Plaintiffs filed a complaint against the

Director and the Labor Commissioner of the State of

California (collectively, the “State”).2 The Complaint alleged

1 The ready-mix drivers do not always have discretion to decide how

much water to add, but must follow instructions from engineers.

2 Plaintiffs also sued Governor Brown, but later dismissed the case as

to him.
ALLIED CONCRETE AND SUPPLY V. IBT 11

that § 1720.9 violates the Equal Protection Clause of the

Constitution, or alternatively, is preempted by the FAAAA,

and sought injunctive and declaratory relief. Before the State

answered the complaint, IBT moved for leave to intervene,

either as of right or permissively. See Fed. R. Civ. P. 24(a) &

(b). On August 22, 2016, Plaintiffs sought a preliminary

injunction on their equal protection claim. Before the court

ruled on Plaintiffs’ motion for injunctive relief, the State

moved to dismiss under Federal Rule of Civil Procedure

12(b)(6).

Subsequently, in September, the district court denied

IBT’s motion to intervene, reasoning that: (1) the union

could not intervene by right because it did not have a

significantly protectable interest in the case; and (2) that the

union could not permissively intervene because it would

cause a delay and the State could protect any interests IBT

may have. IBT appealed the denial of its motion to intervene.

On October 18, 2016, the district court granted Plaintiffs’

motion for a preliminary injunction on the equal protection

claim, finding that § 1720.9 was not likely to survive rational

basis review.3In December, the district court granted the

State’s motion to dismiss Allied Concrete’s FAAAA claim,

but denied the motion as to the equal protection claim. Allied

Concrete appealed the dismissal of its FAAAA claim.

Thereafter, Plaintiffs moved for summary judgment and

requested that the temporary injunction be made permanent. 

The district court, holding that § 1720.9 violated the Equal

Protection Clause, permanently enjoined the statute’s

3 The State appealed the preliminary injunction, but the subsequent

entry of the permanent injunction mooted that appeal.
12 ALLIED CONCRETE AND SUPPLY V. IBT

application and enforcement. First, the district court defined

the classification in § 1720.9 as treating “ready-mixed

concrete drivers differently than other materials drivers.” 

And, although the district court credited the State’s evidence

as to the differences between ready-mix drivers and drivers

of other materials, it concluded – without explanation – that

those differences were immaterial because “all that matters

for inclusion in the [prevailing wage law] is whether or not

drivers are hauling and delivering construction materials to

public works sites.” Thus, the district court concluded that

“in all respects relevant to the [prevailing wage law], readymixed concrete drivers and other materials drivers are

similarly situated.” Recognizing that the State’s interests

may be legitimate, the district court nevertheless struck down

the statute because the classification was “arbitrary” and not

rationally related to any of the interests. The State appealed.

STANDARD OF REVIEW

We review de novo grants of summary judgment and

dismissals. First Resort, Inc. v. Herrera, 860 F.3d 1263,

1271 (9th Cir. 2017), cert. denied, 138 S. Ct. 2709 (2018); Ah

Quin v. Cty. of Kauai Dep’t of Transp., 733 F.3d 267, 270

(9th Cir. 2013).

We consider de novo whether a motion to intervene of

right should have been granted, Canatella v. California,

404 F.3d 1106, 1112 (9th Cir. 2005), and, if necessary,

review for abuse of discretion a denial of permissive

intervention, id. at 1117.
ALLIED CONCRETE AND SUPPLY V. IBT 13

DISCUSSION

1. Equal Protection

The parties agree that the rational basis test applies. 

Therefore, § 1720.9 “cannot run afoul of the Equal Protection

Clause if there is a rational relationship between the disparity

of treatment and some legitimate governmental purpose.” 

Heller v. Doe, 509 U.S. 312, 320 (1993). Non-suspect

classifications are

constitutionally valid if there is a plausible

policy reason for the classification, the

legislative facts on which the classification is

apparently based rationally may have been

considered to be true by the governmental

decisionmaker, and the relationship of the

classification to its goal is not so attenuated as

to render the distinction arbitrary or irrational.

Armour v. City of Indianapolis, 566 U.S. 673, 681 (2012)

(internal quotation marks omitted); see also Johnson v.

Rancho Santiago Cmty. Coll. Dist., 623 F.3d 1011, 1031 (9th

Cir. 2010) (“[A] state action need not actually further a

legitimate interest; it is enough that the governing body

‘could have rationally decided that’ the action would further

that interest.” (quoting Minnesota v. Clover Leaf Creamery

Co., 449 U.S. 456, 466 (1981))). “Further, because the

classification is presumed constitutional, the burden is on the

[party] attacking the legislative arrangement to negative every

conceivable basis which might support it.” Armour, 566 U.S.

at 681 (internal quotation marks omitted); see also Clover

Leaf Creamery Co., 449 U.S. at 464 (“[P]arties challenging

legislation under the Equal Protection Clause . . . cannot
14 ALLIED CONCRETE AND SUPPLY V. IBT

prevail so long as it is evident from all the considerations

presented to [the legislature], and those of which we may take

judicial notice, that the question is at least debatable.”

(second alteration in original ) (internal quotation marks and

citations omitted)); Vance v. Bradley, 440 U.S. 93, 111

(1979) (“[T]hose challenging the legislative judgment must

convince the court that the legislative facts on which the

classification is apparently based could not reasonably be

conceived to be true by the governmental decisionmaker.”).

We disagree with the district court’s conclusion that the

differences between ready-mix drivers and other delivery

drivers is immaterial for the purposes of the prevailing wage

law. As mentioned above, the California Supreme Court has

stated that prevailing wage laws further goals such as: 

(1) generally protecting employees on public works projects,

(2) benefitting the public through the superior efficiency of

well-paid employees, and (3) permitting union contractors to

compete with nonunion contractors. See Lusardi, 824 P.2d at

649. The legislature could have rationally concluded that

extending the prevailing wage law to ready-mix drivers ahead

of other drivers would further these respective goals because

ready-mix drivers: (1) are more integrated into the

construction process than other materials drivers and should

be paid accordingly; (2) are more skilled than other drivers

and provide a material that is more important to public works

projects than other materials such that paying the prevailing

wage will attract superior drivers and improve public works;

and (3) are more likely to be unionized and, therefore,

vulnerable to underbidding.

4 Plaintiffs have not met their

4 Each of these justifications is alone sufficient to survive the rational

basis test. The State and IBT present us with several other potential
ALLIED CONCRETE AND SUPPLY V. IBT 15

high burden of convincing us that these legislative facts

“could not reasonably be conceived to be true by the

governmental decisionmaker.” Bradley, 440 U.S. at 111. 

The legislative facts are at least debatable and the

classification rationally related to furthering the purposes of

the prevailing wage law; as such, the statute survives the

rational basis test.5

See FCC v. Beach Commc’ns, Inc.,

508 U.S. 307, 320 (1993).

A. Benefit Employees on Public Works Projects

First, “[t]he overall purpose of the prevailing wage law

. . . is to benefit and protect employees on public works

projects.” Lusardi, 824 P.2d at 649. In extending the

prevailing wage law to benefit ready-mix drivers, the

legislature could have rationally decided that the delivery of

ready-mix to a public work is part of the “flow of

construction” and should be compensated as such. Not only

would this protect the ready-mix drivers, but if the legislature

believed that the ready-mix drivers were actually more

integrated in construction, the payment of prevailing wages

justifications, but we need not reach those and offer no opinion on whether

they would save the challenged statute.

5 Undergirding our analysis is the idea that the legislature is permitted

to act incrementally in dealing with perceived problems. See City of New

Orleans v. Dukes, 427 U.S. 297, 303 (1976) (per curiam) (“Legislatures

may implement their program step by step in such economic areas,

adopting regulations that only partially ameliorate a perceived evil and

deferring complete elimination ofthe evil to future regulations.” (citations

omitted)); see also Ry. Express Agency v. New York, 336 U.S. 106, 110

(1949) (“It is no requirement of equal protection that all evils of the same

genus be eradicated or none at all.” (citing Cent. Lumber Co. v. South

Dakota, 226 U.S. 157, 160 (1912))).
16 ALLIED CONCRETE AND SUPPLY V. IBT

could increase efficiency in public works projects by

attracting higher-skilled workers.

Specifically, the legislature could have concluded that the

ready-mix drivers are more integrated into the flow of

construction because they bring a perishable commodity to a

construction site, and, in certain instances, need to

incorporate it immediately. During legislative hearings on

the bill, an IBT representative testified:

These workers are part of the construction

process. That’s what’s different and unique

about this from any other material coming to

the job site. You can . . . it’s not dumping a

load of lumber or a bag of nails or whatever

a n d l e a v i n g . Th e y b ri n g t h is

commodity—which is perishable—and [it]

has to be incorporated immediately and the

driver participates in the incorporation process

with the workers. They are part of it. They

move the truck. They operate levers and

equipment that moves the concrete and the

rate of flow in conjunction with the

construction workers. They are integral to the

process.

At least some of the legislators were impressed by this

perceived difference from other materials. As one legislator

stated: “I will be supporting the bill today. I do get the

distinction between the product we’re talking about and

delivering in effect, dumping a delivery of pipes or paint or

steel. This is a different commodity.”
ALLIED CONCRETE AND SUPPLY V. IBT 17

The conclusion that ready-mix drivers are more integral

to the public works projects than other drivers because of the

material’s properties and the driver’s tasks is rational on its

face. Therefore, it is up to Plaintiffs to negate this

justification as inconceivable. Plaintiffs attempt this through

three arguments. They first argue that the delivery of readymix is not any different than that of other materials. For

example, one contractor stated that “[f]rom [his] perspective

as a contractor, there is no meaningful difference between the

delivery of ready-mixed concrete . . . and the delivery of any

other construction material . . . . Approximately 95% of the

time, all of the [ready-mix] goes into a single pump that [his]

employees than [sic] use to place the concrete.” While this

argument raises a factual dispute with the testimony from

IBT’s witness, quoted above, it does not significantly weigh

against the legislature conceivably concluding that ready-mix

drivers are more important to the construction process based

on the properties of the materials, the uniqueness of the

trucks, and the driver’s responsibilities upon arrival. The

legislature, where there is no suspect class at issue, has wide

leewayto consider different, and potentially competing, facts. 

See Armour, 566 U.S. at 685 (“[T]he Constitution does not

require the [government] to draw the perfect line nor even to

draw a line superior to some other line it might have drawn.

It requires only that the line actually drawn be a rational

line.”).

Next, Plaintiffs argue that the legislature could not

rationally conclude that ready-mix drivers were more

integrated into the flow of construction than other drivers

because the Director had previously found that the drivers

were not always entitled to prevailing wages under the pre-

§ 1720.9 test. In A&A Ready Mix Concrete, the Director

concluded that ready-mix drivers delivering the material, but
18 ALLIED CONCRETE AND SUPPLY V. IBT

not performing on-site construction work, were not part of the

flow of construction. Plaintiffs argue that this administrative

ruling undercuts any factual basis for the legislature to have

decided otherwise. This argument fails for several reasons. 

First and foremost, the legislature is not bound to accept the

findings of an administrative agency. Legislatures frequently

change laws in response to administrative (or judicial)

decisions with which they do not agree. As such, this

decision of the agency is of little relevance to our analysis.

Finally, Plaintiffs argue that extending the prevailing

wage to all ready-mix drivers is overbroad because not all

ready-mix drivers are sufficiently integral to the flow of

construction. For example, Plaintiffs contend that not all

drivers incorporate the ready-mix, and that even if they do,

this would not necessarily support higher wages for the drive

time. Again, Plaintiffs question where the legislature drew

the line. But, for the reasons stated above, the legislature

could have rationally concluded that ready-mix drivers were

more integral to public works than other drivers and that the

drive time – when the driver controls the rate of rotation and

the amount of water in the drum – is part of the construction.

B. Ensure Superior Projects

Second, another goal of the prevailing wage law is to

“benefit the public through the superior efficiency of wellpaid employees.” Lusardi, 824 P.2d at 649. The State offers

that the legislature may have decided that the unique aspects

of a ready-mix driver’s job, and the nature of ready-mix as a

material for structural projects such as buildings, bridges, and

dams (as opposed to roads), make the quality of ready-mix

drivers more important to public works projects than other

drivers. This argument rests on two premises that Plaintiffs
ALLIED CONCRETE AND SUPPLY V. IBT 19

challenge: (1) that ready-mix drivers have unique

responsibilities that are more important to the success of a

public works project; and (2) that ready-mix is more often

used in “structural” projects.

As to the first premise, there are clear differences between

ready-mix drivers and other materials drivers relevant to the

equal protection analysis. Ready-mix drivers use specialized

trucks, with a rotating mixing drum, whereas asphalt drivers

use dump trucks. Ready-mix drivers can change the

consistency of their load by adding water to the mixture or

altering the speed of rotation of the drum. Further, ready-mix

drivers require more training than asphalt drivers and must

carry a different driver’s license endorsement than asphalt

drivers. It is conceivable that the legislature could have

rationally believed these facts, determined that ready-mix

drivers need more skills than other drivers, and concluded

that prevailing wages would attract higher-quality workers.

Plaintiffs argue that there is no meaningful difference

between the delivery of ready-mix and other materials. For

example, some contractors declare that ready-mix and asphalt

drivers both merely drop the material where the contractors’

employees tell the driver to dump it. Plaintiffs further argue

that both ready-mix and asphalt have a limited duration in

which they must be delivered. Finally, Plaintiffs argue that

even though the ready-mix driver has the ability to add water

to the mixture, he or she does not have discretion to do so. 

Instead, the drivers simply follow instructions from

somebody else.

Nonetheless, the different licensing requirements and the

ability of ready-mix drivers to control the cement in their

trucks are rational grounds for distinguishing between them
20 ALLIED CONCRETE AND SUPPLY V. IBT

and other drivers. Further, even if ready-mix drivers do not

have discretion to add water to the mixture, or change the

speed of the rotating drum, they still must control these

variables during the drive, which is not true for drivers of

typical dump trucks. Carefully following important

instructions is itself a valuable skill.

As to the second premise, although it is true that many

projects could interchange the materials depending on cost,

there is evidence that ready-mix is used for structural support,

such as walls or footings, more often than other materials. By

contrast, asphalt cannot be used as a structural material, and

is most often used for paving. It is easy to imagine a

legislator concluding that a failed structure, such as a dam or

bridge, is worse than a poorly-paved road. Therefore, the

legislature could have rationally concluded that ready-mix is

more important to sensitive public works and that the drivers

must be more skilled to ensure the integrity of the material

they deliver.

Again, Plaintiffs cannot negate this justification. Aside

from arguing that ready-mix drivers are not any different than

other drivers, Plaintiffs also contend that concerns about

structural projects do not survive constitutional scrutiny

because not all public works are structural projects. But this

argument cannot carry the day under rational basis review. 

See Heller, 509 U.S. at 321 (“[C]ourts are compelled under

rational-basis review to accept a legislature’s generalizations

even when there is an imperfect fit between means and

ends.”).
ALLIED CONCRETE AND SUPPLY V. IBT 21

C. Protect From Underbidding

Third, another purpose of the prevailing wage law is “to

permit union contractors to compete with nonunion

contractors.” Lusardi, 824 P.2d at 649. The district court,

citing Merrifield v. Lockyer, 547 F.3d 978, 991 n.15 (9th Cir.

2008), however, rejected this argument: “[L]egislation

passed for the sole purpose of protecting union employers

from non-union competition will not pass constitutional

muster.” As we further explain below, Merrifield does not

support the district court’s conclusion. True, bare economic

protectionism is not a valid justification for discriminatory

treatment, but the interest in protecting union workers from

underbidding conceivablyis about ensuring a certain standard

of worker – and avoiding a race to the bottom – rather than

granting favors to politically important actors. See O.G.

Sansone, 127 Cal. Rptr. at 813–14 (describing the

maintenance of competition between union and non-union

workers as one of the purposes of the federal prevailing wage

law); see also Indep. Roofing Contractors v. Dep’t of Indus.

Relations, 28 Cal. Rptr. 2d 550, 557 (Ct. App. 1994)

(recognizing the “declared public policy of [California] in

favor of collective bargaining”).

The State argues that the legislature could have rationally

concluded that ready-mix drivers were more vulnerable

to underbidding than other drivers because a higher

percentage of ready-mix drivers are union workers. An IBT

representative estimates that 95% of ready-mix drivers in the

San Francisco area are working under collective bargaining

agreements (“CBAs”), whereas “IBT has only one or two

[CBAs] with contractors who are also commercial suppliers

covering asphalt delivery in California.” If unionized readymix drivers were underbid by a non-union supplier, 95% of
22 ALLIED CONCRETE AND SUPPLY V. IBT

drivers in San Francisco would be ineligible for the job. 

Therefore, it seems reasonable that the legislature could have

rationally believed that underbidding in the ready-mix market

is more harmful and that § 1720.9 would further the interest

in preventing underbidding.

Plaintiffs respond that underbidding by non-union drivers

may be a problem, regardless of the material carried, and that

the state has not provided any evidence that the disparity

between union and non-union rates is greater for ready-mix

drivers than other drivers. These arguments miss the mark. 

Just because underbidding may be an issue for drivers of

other materials does not mean that the legislature could not

have rationally concluded that the problem was more acute

for ready-mix drivers due to their higher unionization rates. 

Second, the state is not required to produce empirical

evidence to support the statute; it is Plaintiffs’ burden is to

negate conceivable justifications. See Beach Commc’ns,

508 U.S. at 315 (“[A] legislative choice . . . may be based on

rational speculation unsupported by evidence or empirical

data.”).

D. Not Bare Economic Protectionism

Plaintiffs contend that they have refuted all of the State’s

justifications and that the only explanation for § 1720.9 is that

the legislature wanted to protect the suppliers of other

materials from competition. Plaintiffs, however, have put

forward no evidence that the legislature engaged in improper

favoritism, and the Ninth Circuit cases that Plaintiffs cite are

inapposite.

Plaintiffs rely on Merrifield for the premise that

“economic protectionism for the sake of economic
ALLIED CONCRETE AND SUPPLY V. IBT 23

protectionism is irrational with respect to determining if a

classification survives rational basis review.” 547 F.3d at 991

n.15. Merrifield, however, presented a unique set of facts

distinguishable from those here. In Merrifield, a pest-control

professional who did not use pesticides challenged, on due

process grounds, the application of California’s overall

pesticide licensing scheme to him and other non-pesticide

users. Id. at 987. We rejected the due process claim,

reasoning that the state had a public safety interest in

“requiring persons who do not use pesticides to learn about

the risks of pesticides . . . because persons like [plaintiff]

work in environments where they may be exposed to

pesticides that have been applied previously and left on-site.” 

Id. at 988.

The plaintiff in Merrifield also challenged, on equal

protection grounds, the exemptions in the licensing scheme,

which exempted pest-control professionals who dealt with

bats, raccoons, skunks, and squirrels and did not use

pesticides from the licensing requirement, but did not

similarly exempt professionals who worked with mice, rats,

or pigeons. Id. at 981–82. Applying the rational basis test,

we struck down these selective exemptions. Id. at 991. We

reasoned that the classification in the licensing scheme did

not survive constitutional muster because it contradicted the

very interest the State proffered to defeat the due process

claim – public health concerns about exposure to pesticide. 

See id. (“We cannot simultaneously uphold the licensing

requirement under due process based on one rationale and

then uphold [plaintiff’s] exclusion from the exemption based

on a completely contradictory rationale.”). The rationale was

contradictory because those pest-control operators who

worked with bats, rats, racoons, skunks, and squirrels were

more at risk of being exposed to pesticides even if they did
24 ALLIED CONCRETE AND SUPPLY V. IBT

not themselves use pesticides than similarly-situated

operators who dealt with more-common pests like mice or

rats. Id. at 991.

Plaintiffs also rely on Fowler Packing Co. v. Lanier,

844 F.3d 809, 816 (9th Cir. 2016). In Fowler Packing, we

concluded, on a motion to dismiss, that plaintiffs had pleaded

an equal protection claim because the only conceivable

explanation for a portion of the challenged legislation was the

need to win the political support of a particular labor union. 

Id. at 816. The legislation at issue in Fowler Packing

“created a ‘safe harbor’ that gave employers an affirmative

defense against” certain minimum wage claims. Id. at 811. 

However, there were carve outs from the safe harbor that only

benefitted the labor union which had ongoing suits against

employers. Id. at 815. These carve outs came in the form of

cut-off dates that corresponded almost exactly to the filing

dates of the labor union’s cases against certain employers. Id. 

Accepting the plaintiffs’ allegations as true, we held that they

had alleged enough to survive a motion to dismiss.

Both cases are easily distinguishable from the situation

here. Unlike in Merrifield, there is no suggestion that

classifying ready-mix drivers as distinct from other drivers

actually contradicts the purposes of the prevailing wage law. 

Similarly, there is no specific evidence like the cut-off dates

in Fowler Packing that clearly suggests improper favoritism. 

Plus, the burden on Plaintiffs here to come forward with

evidence that negates every conceivable basis for the law is

much higher than that of the Fowler Packing plaintiffs

opposing a motion to dismiss.

Finally, Plaintiffs emphasize the fact that asphalt was

dropped from an earlier version of § 1720.9 as a sign that the
ALLIED CONCRETE AND SUPPLY V. IBT 25

law’s only justification is to protect ready-mix suppliers’

competitors. Without more, the fact that the legislature once

considered including asphalt in the legislation is not evidence

of improper motive. In fact, considering asphalt, but then

removing it after holding hearings, could just as easily bolster

the conclusion that after reviewing the facts, the legislature

reached an informed judgment.

Because Plaintiffs have not negated every conceivable

justification for § 1720.9, we conclude that the statute passes

the rational basis test and does not violate the Equal

Protection Clause.

2. Intervention

In a separate appeal, IBT challenges the district court’s

denial of its motion for leave to intervene as of right or by

permission. During oral argument, we raised the issue of

whether IBT’s appeal would be moot if we reversed the

district court on the equal protection claim. IBT argued that

its appeal would not be moot because Plaintiffs could still

move for rehearing en banc or petition for a writ of certiorari

with the Supreme Court.

We are not aware of any decision from our Circuit that

addresses whether a potential petition for rehearing or

certiorari keeps a case alive for the purposes of appealing a

motion to intervene. The typical rule is that “[a]n appeal is

moot if there exists no present controversy as to which

effective relief can be granted.” W. Coast Seafood

Processors Ass’n v. Natural Res. Def. Council, Inc., 643 F.3d

701, 704 (9th Cir. 2011) (internal quotation marks omitted);

see also United States v. Ford, 650 F.2d 1141, 1143 (9th Cir.

1981). On the other hand, where the district court has entered
26 ALLIED CONCRETE AND SUPPLY V. IBT

judgment, but a party has appealed some aspect of the case,

an appeal of the motion to intervene is not moot. See

Canatella, 404 F.3d at 1109 n.1. We think that the situation

here is more similar to Canatella than West Coast Seafood or

Ford. In both West Coast Seafood and Ford, the underlying

litigation had concluded; here, as IBT points out, Plaintiffs

may pursue their case by filing a petition for rehearing or

rehearing en banc here, or by petitioning the Supreme Court

for a writ of certiorari.6 We therefore hold that IBT’s appeal

is not moot in light of our reversal and will reach the district

court’s decision denying intervention. See U.S. Postal Serv.

v. Brennan, 579 F.2d 188, 190 n.1 (2d Cir. 1978) (“Because

application for rehearing has been filed and the time to

petition for certiorari has not expired, the case has not

reached final judgment, and the issue of intervention is not

moot.” (citation omitted)).

To determine whether a party may intervene as of right,

we employ a four-part test: (1) the motion must be timely;

(2) the applicant must claim a “significantly protectable

interest” in the action; (3) the disposition of the action must

as a practical matter impair or impede the applicant’s ability

to protect that interest; and (4) the applicant’s interest may be

inadequately represented by the other parties. Wilderness

Soc’y v. U.S. Forest Serv., 630 F.3d 1173, 1177 (9th Cir.

2011) (en banc).

We have previously considered a motion for IBT to

intervene on the side of the State to defend California’s

prevailing wage law. See Californians for Safe &

6 Plaintiffs have already indicated that they intend to file a petition for

rehearing en banc challenging this Circuit’s FAAAA preemption

precedent.
ALLIED CONCRETE AND SUPPLY V. IBT 27

Competitive Dump Truck Transp. v. Mendonca, 152 F.3d

1184, 1189–90 (9th Cir. 1998). Because the facts of

Mendonca are almost identical to this case, we follow its

reasoning and reverse the district court’s denial of IBT’s

motion to intervene.

In Mendonca, “public works contractors who provide[d]

transportation-related services on publicly-funded projects”

challenged California’s prevailingwage laws, arguing that the

FAAAA preempted the state law. Id. at 1185–86. We

affirmed the district court’s grant of IBT’s motion to

intervene, reasoning that: (1) IBT’s motion was timely;

(2) IBT’s members had a “‘significant interest’ in receiving

the prevailing wage for their services as opposed to a

substandard wage”; (3) “IBT’s members’ right to receive the

prevailing wage” would have been impaired had plaintiffs

prevailed; and (4) IBT demonstrated that the State’s

representation of its interests may have been inadequate

“because the employment interests of IBT’s members were

potentially more narrow and parochial than the interests of

the public at large.” Id. at 1189–90.

The district court attempted to distinguish Mendonca by

emphasizing that we used the phrase “receive the prevailing

wage” in Mendonca. Id. at 1190 (emphasis added). By

emphasizing the word “receive,” the district court assumed

that the IBT members in Mendonca would not have been paid

the prevailing wage if the statute were struck down. Here, on

the other hand, the district court relied on the fact that many

IBT members already received the prevailing wage pursuant

to CBAs – regardless of the prevailing wage law. In other

words, the district court concluded that the IBT members

“would merely lose § 1720.9 as a statutory backstop to their

[CBAs].”
28 ALLIED CONCRETE AND SUPPLY V. IBT

Mendonca is not susceptible to the district court’s narrow

reading. Moreover, we are not convinced that the distinction

between receiving a prevailing wage pursuant to statute and

maintaining the statutory right to receive a wage is a

meaningful one for purposes of assessing standing to

intervene. For one, Mendonca makes no mention of

distinguishing IBT members by whether they actually

received the prevailing wage or not, and there is no

discussion about whether certain IBT members were already

paid the prevailing wage under CBAs. It is entirely possible

that the members at issue in Mendonca were subject to CBAs. 

For another, the district court just as easily could have

emphasized the word “right” in the statement “[if plaintiffs]

prevailed, it would have clearly impaired IBT’s members’

right to receive the prevailing wage” and come to the

opposite conclusion. Id. at 1190. In any event, we do not see

a significant difference either way, even if the Mendonca

intervenors were not subject to CBAs. For example,

receiving a prevailing wage in the absence of a CBA might

technically be different than receiving it pursuant to a

contract, but for the purposes of a significantly protectable

interest, we think they are indistinguishable. Even if all of

IBT’s members are subject to CBAs7that pay them the

prevailing wage, a statutory right to that wage is still

important and not at all speculative. CBAs are not

permanent, and re-negotiating about wages from a statutory

floor is certainly a much better bargaining position than

starting from scratch. Maintaining the statutory floor is a

significant, protectable interest for IBT.

7

IBT alleges that there are times when some of its members are not

protected by CBAs.
ALLIED CONCRETE AND SUPPLY V. IBT 29

Likewise, Mendonca guides us on the other three

elements of intervention by right. First, there is no dispute

that IBT’s motion was timely. Next, because IBT has an

interest in the right to a prevailing wage, the district court

invalidating the law clearly impaired that interest. Id. And,

finally, IBT’s interests are potentially more narrow than the

public’s at large, and the State’s representation of those

interests “may have been inadequate.” Id. (emphasis added).

As such, we see no reason to depart from Mendonca and

therefore conclude that the district court erred in denying

IBT’s motion to intervene as a matter of right.8

3. Preemption

The district court correctly dismissed Plaintiffs’ FAAAA

preemption claim. The prevailing wage law “is not ‘related

to’ . . . prices, routes, and services within the meaning of the

[FAAAA’s] preemption clause.” Mendonca, 152 F.3d at

1189; see also Dilts v. Penske Logistics, LLC, 769 F.3d 637,

647–48 (9th Cir. 2014) (reaffirming Mendonca). Thus,

preemption does not apply.

CONCLUSION

The district court’s summary judgment in favor of

Plaintiffs’ equal protection claim, and its denial of IBT’s

motion for leave to intervene as of right are REVERSED. 

We AFFIRM the district court’s dismissal of Plaintiffs’

8 Because we uphold IBT’s intervention as a matter of right, we need

not reach its alternative motion for permissive intervention.
30 ALLIED CONCRETE AND SUPPLY V. IBT

FAAAA preemption claim. We REMAND to the district

court to enter judgment consistent with this opinion.

The State Defendants and IBT shall recover their costs on

appeal from Plaintiffs.