Arizona Truck Accident Law: FMCSA Rules and Carrier Liability.

Truck crash cases don’t follow the same rules as car accident cases. A second layer of law applies. Federal regulations govern the trucking industry through the Federal Motor Carrier Safety Administration, and those regulations create duties that don’t exist in ordinary car crashes. When a truck driver or carrier violates those duties, the violation itself can establish negligence.

Arizona recorded over 14,000 crashes involving trucks and buses in 2024. When a commercial truck hits a passenger vehicle, 97% of deaths occur in the smaller vehicle. The physics are unforgiving and the law reflects that asymmetry. This guide covers the federal regulations that govern commercial trucking, how Arizona law assigns liability between drivers and carriers, and what injured people need to know about preserving evidence before it disappears.

Federal Regulations That Apply to Every Truck Case

The Federal Motor Carrier Safety Regulations live in Title 49 of the Code of Federal Regulations, Parts 390 through 399. They apply to every motor carrier operating commercial motor vehicles in interstate commerce. That covers the vast majority of commercial trucks on Arizona highways, including those hauling freight on I-10, I-17, and I-40.

These aren’t suggestions. They’re binding federal law. Violations constitute negligence per se in most jurisdictions, meaning the violation itself proves the duty-and-breach elements of a negligence claim.

Hours of Service (49 CFR Part 395)

Hours-of-service rules exist for one reason: tired drivers kill people. The FMCSA’s HOS regulations cap how long a truck driver can operate before resting.

When a truck driver crashes and the ELD data shows an HOS violation, the case gets significantly stronger. The carrier knew or should have known the driver was operating beyond legal limits. For more on how fatigue data plays out on Arizona highways, our investigation into fatigued truckers and HOS violations documents the enforcement gaps in detail.

Electronic Logging Devices (49 CFR Part 395.8)

Since December 2017, most commercial motor vehicles must carry electronic logging devices that automatically record driving time. The ELD mandate replaced paper logbooks, which were easy to falsify. Drivers called them “comic books” because the entries were fiction.

ELDs connect to the vehicle’s engine control module and record engine hours, vehicle movement, miles driven, and the driver’s duty status. The data is time-stamped and GPS-tagged. It’s the most objective evidence in any truck crash case.

The ELD mandate has exceptions. Short-haul drivers operating within a 150-air-mile radius, drivers of vehicles manufactured before 2000, and drivers operating under certain agricultural exemptions aren’t required to use ELDs. These exceptions create gaps that fatigue-related crash cases sometimes fall through.

Vehicle Maintenance (49 CFR Parts 393 and 396)

Federal regulations require carriers to systematically inspect, repair, and maintain every commercial motor vehicle they operate. Part 396 mandates that carriers keep records of all inspections, repairs, and maintenance for each vehicle. Part 393 sets specific equipment standards for brakes, tires, lighting, coupling devices, and frames.

Every driver must perform pre-trip inspections before each trip, covering brakes, tires, steering, lighting, coupling devices, and emergency equipment. The driver must complete a written report, called a Driver Vehicle Inspection Report (DVIR), documenting the vehicle’s condition.

Brake standards under 49 CFR 393.40 through 393.52 set detailed requirements for the brake system itself. Defective brakes are the number one vehicle-related out-of-service violation found during roadside inspections nationally. A loaded 80,000-pound truck with defective brakes can’t stop in time. Period.

Tire standards under 49 CFR 393.75 establish minimum tread depth and prohibit tires with exposed body ply, bumps, or cuts that expose the cord. Tire blowouts from worn or defective tires cause loss-of-control crashes at highway speeds.

When a maintenance defect causes a crash, the carrier’s maintenance records become central evidence. Gaps in those records, missed inspections, deferred repairs, and repeated violations for the same defect all point to systemic negligence.

Carrier Liability vs. Driver Liability

Truck crash cases almost always involve at least two defendants: the driver and the carrier. Understanding how liability attaches to each is essential.

Respondeat Superior

Under the doctrine of respondeat superior, an employer is vicariously liable for the negligent acts of an employee committed within the scope of employment. When a truck driver crashes while performing duties for the carrier, the carrier bears liability for the driver’s negligence.

This doctrine applies to employee drivers without question. The driver was working. The driver was negligent. The employer pays.

The complication arises with independent contractor drivers. Many carriers classify their drivers as independent contractors rather than employees. The carrier argues it doesn’t control how the driver operates, only the result. If the driver is truly an independent contractor, respondeat superior may not apply.

Arizona courts look past the label. The question isn’t what the contract says. It’s how much control the carrier actually exercises over the driver’s work. If the carrier dictates routes, schedules, loads, and equipment standards, the driver is functionally an employee regardless of what the contract calls them. Arizona follows the right to control test.

Direct Negligence Against the Carrier

Respondeat superior isn’t the only path to carrier liability. Carriers can be directly negligent in their own right.

Negligent hiring and negligent retention sit at the front of the list. Carriers must investigate a driver’s background before hiring, including checking the driver’s record through the FMCSA’s Pre-Employment Screening Program. Hiring a driver with a history of safety violations, DUIs, or license suspensions creates direct liability.

Retention liability attaches when the carrier keeps a driver on staff after learning of safety violations, positive drug tests, or repeated incidents. The carrier knew the driver was dangerous and didn’t act.

Negligent supervision is the next tier. Failing to monitor driver compliance with HOS rules, maintenance schedules, and safety protocols is negligent supervision. If the carrier’s own records show the driver routinely exceeded HOS limits and the carrier did nothing, that’s a supervision failure that Maricopa County Superior Court juries take seriously.

Negligent entrustment rounds out the four theories. Allowing a driver to operate a vehicle the carrier knows is defective, or allowing an unqualified driver to operate a vehicle requiring special skills or endorsements, creates negligent entrustment liability on its own.

Each of these claims targets the carrier directly. They don’t depend on the driver’s employment status.

Our investigation into ghost fleets and chameleon carriers on I-10 shows how some carriers dissolve and re-form under new names to escape their safety records. When a carrier disappears after a crash, identifying the successor entity and piercing the corporate structure becomes a critical early step.

Federal Preemption Issues

Federal trucking regulations sometimes conflict with or displace state law claims. This is called federal preemption, and it can narrow or eliminate certain causes of action.

The Federal Aviation Administration Authorization Act of 1994 (FAAAA) includes a preemption clause that prevents states from enacting laws “related to a price, route, or service of any motor carrier.” Courts have interpreted this broadly in some contexts and narrowly in others.

For personal injury claims, the general rule is that federal preemption doesn’t bar state tort actions. A plaintiff can still sue a carrier under Arizona negligence law for injuries caused by a crash. The FMCSA regulations set the floor, not the ceiling. Arizona law can impose additional duties.

Where preemption becomes relevant is in claims that attempt to regulate carrier operations indirectly. State-law claims arguing that a carrier shouldn’t have selected a particular route, or that a carrier’s scheduling practices were negligent, can brush against preemption arguments. Courts evaluate these claims individually.

The practical impact for Arizona plaintiffs: federal regulations create additional duties that strengthen negligence claims. A carrier that violates HOS rules, maintenance requirements, or driver qualification standards has breached a federal duty. That breach supports the state-law negligence claim rather than preempting it.

Insurance Minimums for Commercial Carriers

Federal regulations establish minimum insurance requirements that far exceed Arizona’s passenger vehicle minimums.

49 CFR Part 387 sets the following minimums based on cargo type.

These are minimums. Many carriers carry higher limits, and excess policies are common in the industry. A major trucking company may carry $5 million or more in primary coverage plus umbrella policies.

Arizona’s minimum liability insurance for passenger vehicles is $25,000 per person. The difference between a $25,000 car insurance policy and a $750,000 truck insurance policy reflects the catastrophic damage trucks cause. Even the federal minimum, though, often falls short of covering the full damages in a severe crash. Medical bills, lost future earnings, and pain and suffering from a catastrophic truck crash routinely exceed $1 million.

Arizona Comparative Negligence in Truck Cases

Arizona’s pure comparative negligence system under ARS 12-2505 applies to truck crash cases the same way it applies to any other motor vehicle crash. The plaintiff’s recovery is reduced by their percentage of fault but never eliminated.

In truck cases, insurance companies and defense attorneys work hard to shift fault to the injured driver. Common arguments include the plaintiff was following too closely, failed to maintain their lane, was distracted, or failed to take evasive action.

The comparative fault question matters less in truck cases than in car-versus-car cases, for a simple reason: the truck’s size advantage means even small percentages of truck driver fault produce large liability. A plaintiff found 20% at fault for following too closely still recovers 80% of their damages. If those damages total $2 million, 80% is $1.6 million.

Arizona courts assign fault to all parties, including non-parties. Under ARS 12-2506, a defendant can designate non-parties at fault to reduce its own share. In a truck crash, the carrier might argue that a third vehicle, a road construction company, or the vehicle manufacturer shares fault. Each additional party dilutes the carrier’s percentage.

Spoliation Letters and Evidence Preservation

Evidence in truck crash cases has a shelf life measured in days, not months. A plaintiff’s attorney must act immediately to preserve the following categories of evidence.

ELD data comes first because it has the shortest shelf life. Electronic logging device records show the driver’s hours of service, duty status changes, and GPS location. Carriers can overwrite the underlying data within days if nobody puts them on notice.

Event data recorder (EDR) information lives on the truck itself and captures speed, braking, throttle position, and other data in the seconds before a crash. Some systems overwrite when the vehicle restarts, so the clock starts ticking the moment the truck is moved from the scene.

Dispatch and communication records reveal the operational pressure behind the wheel. Records showing what loads the driver was assigned, delivery deadlines, and communications between the driver and dispatch often reveal whether the carrier pressured the driver to meet unrealistic schedules.

That evidence reframes a single-driver negligence case as a systemic carrier negligence case.

If the carrier destroys evidence after receiving a spoliation letter, or if it destroys evidence it knew or should have known was relevant to anticipated litigation, the court can instruct the jury that the destroyed evidence would have been unfavorable to the carrier. This adverse inference instruction can be devastating to the defense.

Multiple Defendants in Truck Crash Cases

Truck crash litigation typically involves more defendants than a standard car crash case.

Each defendant brings its own insurance policy. A case with four defendants and four separate policies creates a substantially larger pool of available coverage than a case against a single driver with minimum insurance.

Statute of Limitations

Arizona’s statute of limitations for personal injury claims is two years from the date of the crash under ARS 12-542. Wrongful death claims have a separate two-year limitation under ARS 12-611, running from the date of death.

If a government entity is involved, whether through a government-owned vehicle, road design, or maintenance failure, a notice of claim must be served within 180 days under ARS 12-821.01.

For truck crash cases, the two-year window is deceptively tight. Building a truck case requires obtaining and analyzing ELD data, maintenance records, driver qualification files, dispatch records, and often expert analysis from accident reconstructionists, biomechanical engineers, and vocational economists.

Starting late compresses the investigation timeline and weakens the case.