Broadening the FAAAA Safety Exception: Tenth Circuit Adopts a Two‑Step “Genuinely Responsive” Test and Affirms that Delay Can Defeat Irreparable Harm

Introduction

In Colorado Motor Carriers Association v. Town of Vail, the Tenth Circuit addressed the scope of federal preemption under the Federal Aviation Administration Authorization Act (FAAAA) and the Airline Deregulation Act (ADA) in the context of a mountain town’s regulation of delivery vehicles in pedestrian mall areas. The court resolved two pivotal issues:

Whether Vail’s amended ordinance limiting access by high-volume commercial carriers (HVCCs) to pedestrian malls falls within the FAAAA/ADA’s safety exceptions and thus escapes preemption; and
Whether a district court may discount claims of irreparable harm for purposes of a preliminary injunction when a plaintiff waits over a year before suing.

The case pits the Colorado Motor Carriers Association (CMCA), representing trucking companies (including integrated carriers like UPS and FedEx), against the Town of Vail and its Police Chief, Ryan Kenney. Amici curiae included the Colorado Municipal League (for Vail) and the American Trucking Associations (for CMCA).

The dispute arose after Vail’s 2022 ordinance generally prohibited vehicular traffic in pedestrian mall areas but allowed exceptions, including for HVCCs and for deliveries by a Town-approved contractor. In 2023, the Town removed the HVCC exception and opted to channel deliveries through a single contractor using small motorized carts. The district court preliminarily enjoined the 2023 amendment but refused to enjoin the original 2022 scheme. Both sides appealed.

Summary of the Judgment

Writing for the court, Judge Bacharach reversed the preliminary injunction against the 2023 amended ordinance and affirmed the denial of a preliminary injunction against the 2022 ordinance.

FAAAA/ADA Safety Exception: The court held that Vail’s amended ordinance likely falls within the safety exceptions to federal preemption because it regulates “with respect to motor vehicles” and is “genuinely responsive to safety concerns.” The court formally adopted a two-step test—already used by the Second, Fifth, and Ninth Circuits—to assess whether a regulation is “genuinely responsive to safety concerns”: (1) whether safety concerns motivated the regulation; and (2) whether a logical nexus exists between the regulation and safety.
Deference to Local Policymaking: The court emphasized deference to local safety judgments when the nexus to safety is “obvious and logical,” and it rejected the district court’s more searching, means-end scrutiny. It cautioned that closer scrutiny applies where safety rationales appear pretextual or discriminatory.
Preliminary Injunction and Delay: The court affirmed that a district court can discount irreparable harm where a plaintiff delays suit—here, over a year—particularly when the injunction would disturb the status quo. It rejected the notion that success on a preemption claim presumptively establishes the other injunction factors.

Judge Phillips dissented in part, agreeing with the two-step framework but concluding the amended ordinance lacked a logical nexus to safety because it regulates by carrier identity (or ownership/purpose) rather than by vehicle risk characteristics, and any safety-related limits (like small carts) appeared in contracts rather than in the ordinance itself.

Detailed Analysis

I. Precedents Cited and Their Influence

City of Columbus v. Ours Garage & Wrecker Service, Inc., 536 U.S. 424 (2002): The Supreme Court recognized that FAAAA’s safety exception preserves state and local “preexisting and traditional” police powers over motor-vehicle safety, and framed the touchstone as whether a regulation is “genuinely responsive to safety concerns.” The Tenth Circuit placed Ours Garage at the center of its analysis and declined to read it as undermined by later preemption cases. The court further aligned with four circuits that treat “genuinely responsive” as an operative standard (2d, 5th, 9th, 11th).
Loyal Tire & Auto Ctr., Inc. v. Town of Woodbury, 445 F.3d 136 (2d Cir. 2006); United Motorcoach Ass’n, Inc. v. City of Austin, 851 F.3d 489 (5th Cir. 2017); Cal. Tow Truck Ass’n v. City & Cnty. of San Francisco, 693 F.3d 847 (9th Cir. 2012) and 797 F.3d 733 (9th Cir. 2015); Galactic Towing, Inc. v. City of Miami Beach, 341 F.3d 1249 (11th Cir. 2003): These cases articulate or apply the two-step safety inquiry—safety motivation and logical nexus—and inform the Tenth Circuit’s adoption of the same approach. They also support a broad conception of safety authority, coupled with vigilance against pretext or discrimination.
UPS v. Flores-Galarza, 385 F.3d 9 (1st Cir. 2004): The First Circuit found tax-collection measures (licensing/bonding/recordkeeping) not within the safety exception because they did not involve motor-vehicle safety. The Tenth Circuit used this as a boundary marker: the safety exception requires a bona fide motor-vehicle safety connection, not any regulatory burden placed on carriers.
Morales v. Trans World Airlines, Inc., 504 U.S. 374 (1992): The Supreme Court construed “relating to” broadly. The Tenth Circuit equated “with respect to” in the safety exception with “relating to,” underscoring that a regulation qualifies if it has a connection to motor vehicles.
Miller v. C.H. Robinson Worldwide, Inc., 976 F.3d 1016 (9th Cir. 2020); Ye v. GlobalTranz Enters., Inc., 74 F.4th 453 (7th Cir. 2023); Aspen Am. Ins. Co. v. Landstar Ranger, Inc., 65 F.4th 1261 (11th Cir. 2023): These decisions treat “with respect to motor vehicles” as broadly encompassing regulations connected to motor vehicles, bolstering Vail’s position that its pedestrian-mall delivery rules regulate vehicular traffic.
VRC LLC v. City of Dallas, 460 F.3d 607 (5th Cir. 2006): The Fifth Circuit validated municipal reliance on practical experience rather than technical studies to support safety regulations. The Tenth Circuit invoked VRC to reject demands for “documentary evidence” and to support deference to local expertise where the safety rationale is logical.
FCC v. Beach Communications, Inc., 508 U.S. 307 (1993): The “incrementalism” principle: legislatures may approach problems piecemeal. The Tenth Circuit used this to reject the district court’s critique that Vail left other large vehicles (like garbage trucks and buses) in place; perfection is not required for a genuine safety response.
Free the Nipple–Fort Collins v. City of Fort Collins, 916 F.3d 792 (10th Cir. 2019); Osborn v. Durant Bank & Trust (In re Osborn), 24 F.3d 1199 (10th Cir. 1994): These cases establish standards of review for preliminary injunctions and for de novo review when a district court applies an improper legal standard—both critical to the panel’s reversal on the preemption issue.
Schrier v. Univ. of Colo., 427 F.3d 1253 (10th Cir. 2005); Fish v. Kobach, 840 F.3d 710 (10th Cir. 2016); Ng v. Bd. of Regents, 64 F.4th 992 (8th Cir. 2023): These authorities inform the injunction analysis: preserving the status quo; heightened scrutiny for injunctions that disturb it; and the permissibility of treating excessive delay as undermining irreparable harm.
Trans World Airlines, Inc. v. Mattox, 897 F.2d 773 (5th Cir. 1990): The panel rejected CMCA’s reliance on Mattox for any presumption that success on preemption automatically satisfies the remaining injunction factors, clarifying that even where preemption is likely, delay can rebut irreparable harm.
Rodriguez de Quijas v. Shearson/Am. Express, Inc., 490 U.S. 477 (1989): A doctrine-of-precedent touchstone: lower courts must follow controlling Supreme Court language unless and until the Court itself overrules it; the panel used this to preserve Ours Garage’s “genuinely responsive” language.
N. Haven Bd. of Educ. v. Bell, 456 U.S. 512 (1982): The court allowed limited reliance on “postenactment” statements (e.g., the Chief’s email) to illuminate the ordinance’s safety purpose.

II. The Court’s Legal Reasoning

A. The Safety Exception’s Two-Step Test

The Tenth Circuit expressly adopted the two-step approach used in other circuits for applying the FAAAA/ADA safety exception:

Safety Motivation: Was the regulation motivated by legitimate safety concerns?
Logical Nexus: Does the record show an obvious and logical nexus between the regulation and safety?

This framework serves as the lens for determining when a municipal regulation is “genuinely responsive to safety concerns” and thus falls within 49 U.S.C. §§ 14501(c)(2)(A), 41713(b)(4)(B)(i).

B. “With Respect to Motor Vehicles” Is Broad

The court construed “with respect to” as synonymous with “relating to,” meaning any regulation that stands in some relation or connection to motor vehicles qualifies. Vail’s ordinance explicitly regulated “vehicular traffic” in pedestrian mall areas and created delivery-related exceptions; that textual focus on vehicles satisfied the first prong of the safety exception.

C. Step 1: Safety Motivation Established

The ordinance’s text and findings referenced pedestrian safety and the need for a coordinated delivery system. Testimony from Police Chief Ryan Kenney described the pilot program’s safety benefits, persistent efforts to remove or reduce delivery trucks from pedestrian spaces, and the safety-centered rationale for transitioning to small motorized carts operated by a single contractor. The court accepted that safety was a genuine motivation, even if companionship goals (like improving the “guest experience”) also existed; a mixed motive is not disqualifying.

D. Step 2: Logical Nexus and Deference to Local Policymaking

The district court concluded the amended ordinance lacked a logical nexus because it regulates based on carrier identity/ownership and permits other large vehicles (buses, armored trucks, garbage trucks). The Tenth Circuit held the district court applied too demanding a standard and improperly substituted judicial preferences for local policy judgments:

Logical link: Before the amendment, 2–6 large box trucks from HVCCs regularly entered the pedestrian malls. The town’s switch to a contractor using small carts placed drivers at pedestrians’ line of sight, improved maneuverability in crowded, lane-less environments, and reduced impediments to emergency vehicles—benefits that are “obvious and logical.”
No evidentiary overkill required: Municipalities need not produce “documentary evidence, reports, or studies.” Legislative intent and experience-based testimony suffice where the nexus is facially sensible.
Incrementalism is permissible: Leaving other large-vehicle exceptions in place does not break the nexus; legislatures can proceed step-by-step as they work toward broader safety solutions. The record showed Vail continued exploring ways to remove or reduce other large vehicles as well.
No demonstrated pretext or discrimination: While courts scrutinize economic protectionism disguised as safety, the record here showed the single-contractor model was a means to a safety end (uniform small vehicles, better control), not an end in itself. Absent evidence of pretext or discriminatory targeting, deference applies.

E. Preliminary Injunction: Delay and the Status Quo

The court affirmed denial of a preliminary injunction against the original ordinance based on CMCA’s year-long delay in suing, holding that:

Status quo matters: Preliminary injunctions are meant to preserve the status quo; orders that would disrupt it are disfavored and require a stronger showing.
Delay undercuts irreparable harm: While delay is not categorically dispositive, an unreasonable delay can weigh heavily against irreparable harm. CMCA’s only proffered justification (a change in treatment of FedEx Freight) did not explain the broader association-wide delay.
No presumption fills the gap: The court rejected any presumption that success on a preemption theory automatically satisfies irreparable harm, balance of equities, or public interest.

III. The Dissent

Judge Phillips agreed with the majority’s two-step test and the finding that safety motivations existed. He parted ways at the “logical nexus” step:

Carrier-based restrictions: He emphasized that the ordinance regulates by carrier identity or purpose, not by vehicle risk attributes (size, frequency), and allows the town’s contractor to drive the same large vehicles previously used by HVCCs.
Contract vs. ordinance: Any small-vehicle obligations exist only in contract and could be altered by the Town, leaving the ordinance textually unmoored to safety outcomes. Courts should not rely on extrinsic contractual promises to save an ordinance that, on its face and in effect, lacks a safety nexus.
Empirical record: In light of evidence that UPS and FedEx had not caused injuries or violations, and without proof the contractor’s driver safety record is superior, the dissent saw no rational basis for distinguishing carriers if the safety concern is large-vehicle hazards.

The dissent thus would have affirmed the district court’s injunction against the amended ordinance.

IV. Practical Impact and Forward-Looking Implications

A. For Municipalities

Adopt the two-step template: Articulate safety findings in the ordinance and build a record that shows practical, experience-based reasons why the regulation advances safety.
Deference where logic is apparent: Courts will defer when the safety nexus is intuitive (e.g., replacing large box trucks with smaller carts in crowded pedestrian areas).
Incremental regulation is permitted: You can tackle the biggest, most frequent risks first without simultaneously solving every safety issue.
Beware of pretext: If an ordinance appears to favor local contractors or burden particular carriers without safety justification, expect closer scrutiny. Avoid discriminatory carve-outs disconnected from risk.
Contracting models can pass muster: A single-contractor or permit-based system can be within the safety exception if the objective is safety (standardized equipment/operations) and the record supports that objective.

B. For Carriers and Industry

Preemption arguments narrowed: Where municipalities connect restrictions to motor-vehicle safety, FAAAA/ADA preemption arguments face headwinds under this decision.
Focus on pretext and discrimination: The most promising challenges will marshal evidence that safety rationales are post hoc, thin, or discriminatory; or that the ordinance targets identity in a way that bears no relation to risk.
Record matters: If safety performance is excellent and the municipality tolerates comparable risks from favored entities, highlight inconsistencies to question the “logical nexus.”

C. Litigation Strategy on Preliminary Injunctions

File promptly: Significant delay can undermine irreparable-harm showings, even in preemption cases.
Preserve the status quo narrative: Tailor requested relief to maintain, rather than disrupt, the operative regulatory baseline.
No shortcut from merits to harm: Do not rely on a presumption that likely success on preemption suffices for the remaining injunction factors.

D. Circuit Alignment and Doctrinal Clarity

Alignment: The Tenth Circuit now expressly joins the Second, Fifth, Ninth, and Eleventh Circuits in using the two-step “genuinely responsive” test and in reading the safety exception broadly.
Open questions: How much reliance on contracts, post-enactment statements, or policy experience is too much? When does identity-based access become an impermissible proxy for economic favoritism? The dissent signals a potential limit if the ordinance’s text does not itself constrain risk factors.

Complex Concepts Simplified

FAAAA/ADA Preemption: These federal laws generally stop states and cities from regulating the “routes or services” of carriers. But they allow safety regulations concerning motor vehicles.
Safety Exception: A local rule survives preemption if it (1) is “with respect to motor vehicles,” and (2) is “genuinely responsive to safety concerns.”
Two-Step Test: Courts ask (1) did safety motivate the rule? and (2) is there a logical, obvious connection between the rule and safety?
“With respect to”: Broadly means “related to.” If the rule focuses on vehicles in some meaningful way, it qualifies.
Logical Nexus: A common-sense connection is enough; municipalities need not produce formal studies, especially where the safety logic is apparent.
Pretext/Discrimination: If “safety” is a façade for economic protectionism or carrier-specific discrimination, courts will scrutinize closely and may reject the safety exception.
Status Quo in Injunctions: Preliminary injunctions aim to keep things as they were when the dispute arose. Relief that changes the status quo requires a stronger showing.
Delay and Irreparable Harm: Waiting too long to sue can weaken claims of urgent, irreparable injury, undermining preliminary injunctions.

Conclusion

Colorado Motor Carriers Association v. Town of Vail establishes two important precedents in the Tenth Circuit. First, it adopts and applies a two-step “genuinely responsive to safety concerns” test for the FAAAA/ADA safety exception, interpreting “with respect to motor vehicles” broadly and granting substantial deference to local safety policymaking when the nexus to safety is obvious. The decision affirms that municipalities can use contractor-based, small-vehicle delivery systems in pedestrian spaces to reduce risks posed by larger trucks, without falling afoul of federal preemption—so long as the record shows legitimate safety motivations and a logical safety connection.

Second, the court clarifies preliminary injunction practice: delay can undercut irreparable harm, particularly where the requested relief would disrupt the status quo. Success on preemption does not obviate the need to establish the remaining injunction factors.

The dissent warns that deference must not eclipse the requirement for a genuine safety nexus in the ordinance’s own terms and effects, cautioning against reliance on changeable contractual commitments to sustain municipal regulations. That tension—between deference to local safety judgments and the need for textually grounded, risk-based regulation—will likely shape future litigations at the intersection of municipal logistics, pedestrian safety, and federal preemption.