Who Is Liable in a Truck Accident in Arizona?

Figuring out who is liable in a truck accident is often more complicated than it looks. In a car crash, the at-fault driver and their insurer are usually the main focus. In a crash with a commercial truck on a Phoenix freeway, responsibility may be spread across the driver, the trucking company, and several other businesses that touched the truck or its load. This guide walks through each possible party and explains how Arizona divides fault between them. Our Phoenix truck accident guide covers the rest of the claim process.

Why liability matters in Phoenix truck crashes

The Valley is a freight hub. Distribution centers along the Loop 303 and in the West Valley, delivery routes across Phoenix, Tempe and Mesa, and long-haul traffic on I-10 and I-17 all put large trucks next to everyday drivers. A single load may involve a shipper in one state, a broker in another, and a carrier based somewhere else.

Arizona generally makes each defendant pay only its own share of fault (A.R.S. 12-2506 (opens in a new tab)). That means if a responsible party is left out, part of the fault may be assigned to someone you cannot recover from. Identifying everyone involved early can make a real difference.

The possible liable parties

The truck driver

The driver may be at fault for speeding, following too closely, unsafe lane changes, distraction, impairment or driving while fatigued. Federal rules bar a driver from operating a commercial truck while too tired or ill to drive safely, and bar the carrier from requiring or permitting it (49 CFR 392.3 (opens in a new tab)). Fatigue and log violations are covered in our guide to hours of service violations.

The motor carrier (trucking company)

The trucking company is often the main defendant. It may be responsible in two ways.

For the driver's conduct. An employer can generally be held responsible for an employee's negligence within the scope of employment. Arizona's fault statute also makes a party responsible for the fault of someone acting as its agent or servant (A.R.S. 12-2506(D) (opens in a new tab)). Carriers sometimes argue a driver was an independent contractor. Federal leasing rules and the facts of the relationship can affect that argument. When a carrier leases a truck from an owner-operator, the lease must give the carrier exclusive possession, control and use of the equipment and complete responsibility for its operation during the lease, although the rule says this alone does not decide whether the driver is an employee or an independent contractor (49 CFR 376.12(c) (opens in a new tab)).

For its own failures. A carrier may be directly responsible for negligent hiring, training, supervision or retention. It may also be responsible for poor maintenance or pushing unrealistic schedules. Federal rules require carriers to check a driver's qualifications (49 CFR Part 391 (opens in a new tab)) and to inspect and maintain their trucks (49 CFR Part 396 (opens in a new tab)).

The freight broker

A freight broker arranges for a carrier to haul a load but does not usually operate the truck. Brokers have long argued that federal law shields them from negligence claims. On May 14, 2026, the U.S. Supreme Court held in Montgomery v. Caribe Transport II, LLC (opens in a new tab) that a state-law claim that a broker negligently hired an unsafe motor carrier falls within the federal law's safety exception for motor vehicles, so the claim is not preempted.

That does not make a broker automatically responsible. A claim may depend on what the broker knew or should have known about the carrier's safety record.

The shipper and the loader

The company that packed or loaded the trailer may share fault if cargo was overloaded, unbalanced or poorly secured. Shifting cargo can contribute to rollovers and jackknifes. Federal cargo securement rules appear in 49 CFR Part 393 (opens in a new tab).

The maintenance company or mechanic

Many carriers use outside shops for brake work, tire service and inspections. If a shop did faulty work or missed an obvious defect, it may share fault. Maintenance and inspection records, which carriers must keep under 49 CFR 396.3 (opens in a new tab), can help show what work was done and when.

The truck or parts manufacturer

A defect in the truck, trailer, brakes, tires, steering or underride guard may give rise to a product liability claim against the manufacturer or seller (A.R.S. 12-681 (opens in a new tab)). These claims generally follow the two-year deadline, and a claim that arises more than 12 years after the product was first sold generally cannot be brought unless it is based on the maker's or seller's negligence or an express warranty (A.R.S. 12-551 (opens in a new tab)). Arizona's fault statute expressly includes products liability within the definition of "fault" (A.R.S. 12-2506(F) (opens in a new tab)).

A government entity

Sometimes the road itself plays a role: a poorly designed interchange, missing signs, a malfunctioning signal, or an unsafe work zone. In those cases, a city, county or the State of Arizona may share fault. Work zone crashes are covered in our guide to work zone truck accidents.

Claims against public entities follow special rules:

• Notice of claim within 180 days. A claim must be filed with the person authorized to accept service for the public entity within 180 days after the cause of action accrues. It must include facts explaining the basis for liability and a specific amount for which the claim can be settled, with supporting facts. A claim not filed in time is barred (A.R.S. 12-821.01 (opens in a new tab)).

• Lawsuit within one year. Actions against a public entity or public employee generally must be brought within one year after the cause of action accrues (A.R.S. 12-821 (opens in a new tab)).

• Road design defense. A public entity has an affirmative defense if a road's plan or design followed generally accepted engineering or design standards and reasonably adequate warning was given of any unreasonably dangerous condition (A.R.S. 12-820.03 (opens in a new tab)).

Arizona law: comparative fault and fault allocation

Pure comparative fault (A.R.S. 12-2505)

Arizona follows a "pure" comparative fault system. Under A.R.S. 12-2505 (opens in a new tab), if you were partly at fault, your claim is not barred. Instead, your full damages are reduced in proportion to your share of fault.

For example, if a jury found you 20% at fault, any award would be reduced by 20%. This is an illustration only, not a prediction about any case.

The statute also says comparative fault is a question of fact for the jury. There is an exception: a claimant who intentionally, wilfully or wantonly caused or contributed to the injury is not entitled to comparative negligence (A.R.S. 12-2505(A) (opens in a new tab)).

Do not assume you were at fault just because the trucking company's insurer says so. Evidence such as ELD logs, engine data and dashcam video may tell a different story. See our guide to truck accident evidence.

Several liability and fault allocation (A.R.S. 12-2506)

Under A.R.S. 12-2506(A) (opens in a new tab), each defendant is generally liable only for the share of damages that matches its percentage of fault. The jury assigns percentages to every person whose fault contributed to the injury.

A few points matter in truck cases:

• Nonparties can be blamed. The fault of a nonparty may be considered if the plaintiff settled with that nonparty or if a defendant gives notice before trial, as required by court rule (A.R.S. 12-2506(B) (opens in a new tab)).

• Joint liability still applies in some situations. Under A.R.S. 12-2506(D) (opens in a new tab), parties are jointly liable if they were acting in concert, or if one was acting as the agent or servant of the other. There is also an exception for certain claims under the Federal Employers' Liability Act.

• "Fault" is broad. It includes negligence, strict liability, products liability and other breaches of legal duty (A.R.S. 12-2506(F) (opens in a new tab)).

Because of these rules, leaving a responsible company out of a claim can reduce what you recover.

What to do: steps to identify every liable party

1. Get medical care. Your health comes first.

2. Note the truck's markings. Photograph the company name, USDOT number and trailer markings if you can do so safely.

3. Get the police report. It may list the carrier, the vehicle owner and witnesses.

4. Preserve evidence early. A preservation letter can ask the carrier, broker, shipper and repair shop to keep records.

5. Trace the load. Bills of lading, rate confirmations and dispatch records can identify the broker, shipper and loader.

6. Check the road. Photos of signs, lane markings, construction and signals can help show whether a public entity should be on notice.

7. Find every policy. Each liable party may have its own insurance. Learn how coverage works in our guide to truck insurance limits.

Delivery trucks and other special cases

Not every truck crash involves a tractor-trailer. Box trucks, vans and last-mile delivery vehicles raise their own questions, including whether a driver was an employee, an independent contractor or working through a delivery service partner. Our guide to delivery truck and van accidents covers those situations.

If you were injured while working, a workers' compensation claim and a third-party claim against a negligent trucking company may both be possible. See our guide for people hurt on the job by a truck.

For an overview of how these cases are handled from start to finish, visit our Phoenix truck accident lawyer page.