Comparative Fault in Utah Personal Injury Cases: How the 50% Bar Plays Out at Trial

Utah's comparative fault doctrine, codified at Utah Code Section 78B-5-818, is the single most consequential rule in any contested personal injury case in the state. The headline number is familiar to most practitioners: if the plaintiff is found 50 percent or more at fault, recovery is barred entirely. What the headline obscures is how the allocation is actually litigated: defense counsel typically targets the percentage breakdown, and in multi-defendant scenarios, the bar interacts with joint and several liability in ways that catch even experienced practitioners off guard.

This article walks through the framework as it sits in code, the apportionment mechanics, the most consequential trial-stage tactics, and the cross-cutting issues with the no-fault PIP system and uninsured/underinsured motorist coverage.

The statutory framework

Section 78B-5-818 establishes Utah's modified comparative fault rule. Three operative provisions matter:

Subsection (1): The fault of a person seeking recovery is compared to the combined fault of all other defendants, third-party defendants, and identifiable non-parties. The comparison is a single global allocation that must sum to 100 percent.

Subsection (2): If the plaintiff's fault is less than the combined fault of all others (less than 50 percent), recovery is allowed but reduced by the plaintiff's percentage of fault.

Subsection (3): If the plaintiff's fault is equal to or greater than the combined fault of all others (50 percent or more), recovery is barred entirely.

The 50 percent bar is the hard line. A jury finding of 49 percent plaintiff fault preserves the claim and reduces damages by 49 percent. A jury finding of 50 percent plaintiff fault wipes the claim out completely.

Apportionment in practice

The jury makes the allocation as a finding of fact, typically through a special verdict form. The judge instructs on the rule but does not direct the percentages. Three apportionment scenarios appear regularly:

Two-party scenarios. Plaintiff vs. one defendant. The jury allocates a percentage to each, which must sum to 100. Most common in rear-end and intersection collision cases.

Multi-defendant scenarios. Plaintiff vs. two or more defendants. The jury allocates a percentage to the plaintiff and to each defendant separately. Plaintiff's percentage is compared to the combined defendant percentages for the 50 percent bar analysis.

Empty chair scenarios. Plaintiff vs. one defendant, with an identifiable non-party (sometimes called the "phantom defendant"). The defense argues that the non-party contributed to the fault. The jury may apportion fault to the non-party even if no judgment will be entered against them. The plaintiff's percentage is still compared to the combined fault of all others, including the empty chair.

The empty-chair scenario is the defense bar's most common comparative-fault tactic. By naming an absent or judgment-proof third party as bearing fault, defense counsel can shift the allocation arithmetic and push the plaintiff toward the 50 percent bar.

What "fault" means under Section 78B-5-818

The statute's definition of fault is broader than negligence. It includes any act or omission that proximately causes injury, including negligence, breach of warranty or contract, assumption of risk, misuse of a product, and intentional acts.

For practical purposes in crash cases, fault almost always reduces to the following:

• Failure to maintain a proper lookout
• Failure to maintain a safe following distance
• Failure to yield right of way
• Speeding
• Distracted driving (cell phone use, eating, programming GPS)
• Driving under the influence
• Failure to use turn signals or other required communications
• Equipment failures the driver knew or should have known about

The jury may consider any combination of these in allocating fault to a party. The defense will lean heavily on whichever factors apply to the plaintiff to raise the plaintiff's percentage.

Joint and several liability after comparative fault

Utah eliminated traditional joint and several liability with the comparative fault statute. Under Section 78B-5-820, each defendant is severally liable only for their proportionate share of the judgment based on the jury's allocation. There is no joint liability.

The practical effect: in a multi-defendant case where one defendant is judgment-proof, the plaintiff cannot collect that defendant's share from the other defendants. If Defendant A is 30 percent at fault but judgment-proof, and Defendant B is 30 percent at fault and solvent, the plaintiff collects only Defendant B's 30 percent share.

This rule makes the empty-chair tactic more consequential than it would be under a joint-and-several liability regime. Every percent shifted to an empty chair is a percent the plaintiff cannot recover from the defendants who actually pay.

Defense tactics at trial

Defense counsel has a predictable playbook for comparative fault at trial:

1. Mechanism-of-injury cross-examination. Defense will probe whether the plaintiff was wearing a seatbelt, whether the plaintiff had hands on the wheel at the moment of impact, whether the plaintiff was looking forward, or whether the plaintiff had any distractions. Each affirmative answer is a percentage point of comparative fault.

2. Pre-existing condition emphasis. If the plaintiff has any pre-existing injury or condition, the defense will argue that the plaintiff's failure to fully recover from the crash is partly attributable to that pre-existing condition. This is technically a damages argument rather than a fault argument, but juries often blur the distinction in their allocation.

3. Mitigation-of-damages framing. Defense will argue that any gap in treatment, any non-compliance with medical advice, or any return to work too early is the plaintiff's failure to mitigate. Again, technically a damages issue, but juries blend it into fault.

4. Empty chair allocation. As discussed above. The defense identifies any plausible third-party contributor and asks the jury to allocate fault to that absent party.

5. Comparative speeding. If both drivers were arguably speeding (one substantially, the other marginally), the defense will argue that both contributed and the plaintiff's marginal speeding is fault.

The plaintiff's job at trial is to anticipate and rebut each of these in the case-in-chief, then carry the rebuttal through the closing argument with explicit reference to the percentage allocation the plaintiff is seeking from the jury.

Interaction with no-fault PIP

Section 78B-5-818 governs the tort claim after the plaintiff has crossed the no-fault PIP threshold under Section 31A-22-309. The comparative fault reduction applies to the tort recovery, not to PIP benefits.

In practice, PIP pays the first $3,000 in medical bills regardless of fault. If the plaintiff is later found 30 percent at fault, the tort recovery (separate from PIP) is reduced by 30 percent, but the PIP benefits already paid are not affected.

This means a plaintiff who is at fault has a partial recovery floor: PIP benefits are not subject to comparative reduction. For plaintiffs who are found 50 percent or more at fault and barred from tort recovery, PIP benefits remain intact. The PIP is the only recovery available in that scenario.

Interaction with uninsured/underinsured motorist coverage

UM/UIM benefits under the plaintiff's own policy are subject to the same comparative fault analysis as a tort claim. If the plaintiff is 30 percent at fault, the UM/UIM benefits are reduced by 30 percent. This is consistent with the policy language in standard Utah auto policies and has been confirmed in case law.

The practical effect: defense counsel for the at-fault driver and the UM/UIM carrier for the plaintiff often share the same fault-allocation interest. Both want the plaintiff's percentage as high as possible. The plaintiff is litigating against two aligned adversaries on the same issue.

Practical takeaways for practitioners

Plaintiff's counsel:

1. Build the fault-allocation argument into the case-in-chief. Do not wait until closing to explain why the plaintiff bears minimal or zero fault. Tee up each comparative argument the defense will raise, and rebut it in your witness testimony.
2. Anticipate the empty chair. In any multi-vehicle or product-defect case, identify potential empty-chair candidates early. Either include them as defendants or build the affirmative case that their contribution to fault is zero.
3. Treat the 50 percent bar as the actual stakes. A jury finding of 50 percent plaintiff fault is a total defeat. The case is not won by narrowly getting under 50 percent; it is won by establishing the plaintiff's fault at a meaningful margin below 50 percent.

Defense counsel:

1. The 50 percent bar is the goal. Every percent shifted to the plaintiff matters. Cross-examine for it. Argue for it. Frame the empty chair to support it.
2. Allocate fault among co-defendants strategically. Under several liabilities, your client only pays its own share. Pushing fault to a co-defendant reduces your client's exposure.

For all parties, the fault allocation is a finding of fact by the jury. The judge sets the legal framework. The lawyers argue the percentages. The jury fills in the numbers. Every trial decision should be evaluated against how it moves the percentage allocation in your direction.