Montana Auto Insurance & Crash Law · Citizen Guide
Montana Comparative Fault & Motor-Vehicle Crash Liability
A Montana crash does not always have one person who is 100 percent at fault. Montana compares causally relevant negligence among the people responsible for the occurrence. The injured claimant's percentage can reduce the recovery—and if it crosses Montana's statutory threshold, can bar the negligence recovery entirely.
Montana uses a modified comparative-negligence rule
Under MCA § 27-1-702, a claimant's negligence does not bar recovery when it is not greater than the negligence used for the statutory comparison. The claimant's damages are then reduced in proportion to the claimant's own negligence.
Claimant 25% negligent
Recover 75%If total damages are $100,000, a 25% claimant allocation ordinarily reduces the negligence recovery to $75,000 before other legally applicable adjustments.
Claimant 50% negligent
Recover 50%Montana uses “not greater than” language. Equal negligence does not, by itself, bar recovery.
Claimant 51% negligent
No RecoveryIf the claimant's negligence is greater than the opposing negligence used for the statutory comparison, § 27-1-702 bars the negligence recovery.
Multiple defendants: compare the claimant against their combined negligence
When recovery is sought against multiple concurrent negligent defendants, § 27-1-702 compares the claimant's negligence with the combined negligence of those defendants.
| Person | Negligence |
|---|---|
| Claimant | 45% |
| Driver A | 35% |
| Driver B | 20% |
The claimant's 45% is compared against the defendants' combined 55%. Recovery therefore is not barred merely because neither Driver A nor Driver B individually exceeds the claimant's percentage.
The 50% threshold and defendant payment responsibility are different calculations
Montana comparative-negligence analysis ordinarily requires at least two steps:
- determine whether the claimant's own negligence permits recovery under § 27-1-702; and
- apply current § 27-1-703 to determine how responsibility is allocated among defendants and other persons the statute permits the factfinder to consider.
Current § 27-1-703 generally limits a defendant at 50% or less to that defendant's share
Under the current operative text of MCA § 27-1-703, a party whose negligence is determined to be 50% or less of the combined negligence described by the statute generally is severally liable only and is responsible for the percentage attributed to that party, subject to statutory exceptions.
Broader liability remains possible under the statute
Current § 27-1-703 retains joint-liability principles in specified situations, including where:
- persons acted in concert in contributing to the claimant's damages; or
- one party acted as the agent of another.
Montana does not permit an unrestricted “empty chair” defense
Under the current operative § 27-1-703, another person whose negligence may have contributed can be joined as an additional party on an appropriate motion.
Except for persons with whom the claimant settled or whom the claimant released, the statute prohibits comparison with:
- a person immune from liability to the claimant
- a person not subject to the court's jurisdiction
- a person who could have been, but was not, named as a third party
Settled and released tortfeasors are treated differently
Current § 27-1-703 expressly permits the negligence of a person with whom the claimant settled or whom the claimant released to be considered by the factfinder.
MCA § 27-1-704 likewise provides that a release of one tortfeasor:
- does not automatically discharge another tortfeasor's several pro rata liability unless the agreement provides otherwise;
- reduces the aggregate claim against remaining tortfeasors by the percentage ultimately attributed to the settling or released tortfeasor; and
- discharges the settling tortfeasor from contribution liability.
A defendant blaming a settled or released person must prove the fault
Section 27-1-703 places the burden on the defendant asserting fault of a settled or released person to establish:
- that person's negligence
- the applicable standard of care
- causal contribution under the governing law
The statute also contains affirmative-pleading and notice requirements, including procedural protections for the claimant and the settled or released person.
A traffic violation can establish negligence without establishing the final fault percentage
Montana traffic statutes can establish duties of motor-vehicle conduct. A qualifying statutory violation may constitute negligence per se.
But negligence per se does not ordinarily eliminate comparative negligence.
Reed v. Little
Reed v. Little, 209 Mont. 199, 680 P.2d 937 (1984), involved a rear-end crash and competing evidence about the conduct of both motorists.
Montana held that a traffic-statute violation by one driver did not remove causally relevant negligence by the other driver from the comparative analysis.
Giambra v. Kelsey
Giambra v. Kelsey, 2007 MT 158, 338 Mont. 19, 162 P.3d 134, expressly reaffirmed that a negligence-per-se claim or finding does not, absent contrary statutory direction, eliminate comparative-negligence allocation.
Tonner v. Cirian
Tonner v. Cirian, 2012 MT 314, 367 Mont. 487, 291 P.3d 1182, involved an uncontrolled intersection and an asserted statutory right-of-way violation.
The Montana Supreme Court reversed summary judgment because evidence concerning the favored driver's lookout and the disfavored driver's conduct created material comparative-negligence questions.
Fahrnow: Montana's recent crash case reinforces that fault is usually an evidence question
Fahrnow v. E-5 Oilfield Services, 2025 MT 220, arose from two closely timed crashes on an icy Montana highway.
After the first collision, Fahrnow was outside his vehicle in the roadway. E-5 argued that he acted negligently by leaving the vehicle in the travel lane, failing to deploy warning devices and remaining exposed to traffic.
Evidence also supported an argument that E-5's commercial driver failed to operate the hot-oil truck carefully for the icy conditions, failed to respond safely to hazards in plain view, or crossed into the opposing lane before striking Fahrnow.
The district court concluded that Fahrnow alone was responsible and granted summary judgment for E-5.
The Court also reaffirmed that even evidence establishing negligence per se does not remove other causally relevant negligence from Montana's comparative analysis.
A crash type is not a legal fault percentage
Lookout
Was each driver reasonably observing traffic, pedestrians, road conditions and hazards?
Speed
Was speed lawful and reasonable for traffic, weather, visibility, surface conditions and roadway geometry?
Following distance
Did the following driver maintain sufficient distance to respond reasonably to foreseeable traffic conditions?
Right of way
Which driver had statutory priority, and did either person's separate negligent conduct contribute to the collision?
Signals and positioning
Were turns, lane changes, slowing, stopping and vehicle position handled as required by law and ordinary care?
Avoidance
Once a danger became apparent, did either participant have a reasonable opportunity to avoid or reduce the crash?
Negligence alone does not earn a fault percentage—causation still matters
Comparative negligence concerns conduct that legally and factually contributed to the crash or the injury for which damages are sought.
Was the conduct negligent?
Did that negligence cause or contribute to the crash or injury?
A mistake unrelated to the occurrence should not receive a percentage merely because it can be characterized as careless.
Passenger negligence must be proved separately
The driver's negligence is not automatically imputed to an injured passenger.
If the passenger independently engaged in negligent conduct that contributed to the injury, that conduct requires its own duty, breach and causation analysis.
Seat-belt nonuse is not comparative negligence in Montana
MCA § 61-13-106 expressly provides that evidence of compliance or failure to comply with Montana's seat-belt-use requirement is not admissible in a civil action for personal injury or property damage resulting from use or operation of a motor vehicle.
The statute also expressly provides that failure to comply does not constitute negligence.
An insurance company's percentage is not the final civil fault allocation
During claim handling an insurer may assign:
- 100 / 0;
- 80 / 20;
- 50 / 50; or
- another internal liability allocation.
That is an insurer's claim evaluation—not a binding judicial determination.
A traffic citation also is not a final civil percentage
Traffic enforcement and civil negligence serve different legal functions. A violation may be relevant to duty and negligence per se, but comparative negligence still requires causation and evaluation of the other participants' conduct.
Comparative-fault investigation workflow
Evidence that can change the fault allocation
- scene photographs
- vehicle photographs
- roadway measurements
- skid and tire marks
- debris field
- traffic-signal timing
- intersection geometry
- sight-distance evidence
- weather records
- road-surface evidence
- lighting conditions
- event data recorder data
- vehicle telematics
- dash-camera video
- surveillance video
- body-camera video
- 911 recordings
- witness statements
- driver statements
- cellphone evidence
- GPS evidence
- commercial-driver records
- vehicle inspections
- mechanical evidence
- warning-device evidence
- hazard-light evidence
- traffic-control evidence
- reconstruction analysis
- settlement agreements
- releases
Common comparative-fault mistakes
- Stating that a 50% negligent claimant is automatically barred.
- Comparing the claimant separately against each concurrent defendant for the § 27-1-702 threshold.
- Confusing claimant-damage reduction with defendant payment allocation.
- Using an outdated version of § 27-1-703.
- Ignoring the current statute's joinder provisions.
- Allowing an unrestricted “empty chair” allocation.
- Ignoring a settled or released tortfeasor's potential percentage.
- Failing to plead and prove fault attributed to a settled person.
- Assuming a traffic violation establishes 100% liability.
- Assuming right of way eliminates all duties of lookout and reasonable care.
- Assigning fault to negligent conduct that did not cause or contribute to the loss.
- Treating a rear-end collision as an automatic percentage.
- Treating a police citation as the final civil determination.
- Treating the insurer's internal allocation as binding.
- Automatically imputing driver negligence to a passenger.
- Using seat-belt nonuse as comparative-negligence evidence.
- Ignoring employment or agency when applying multiple-defendant rules.
- Waiting too long to preserve crash evidence.
Montana authority map
Frequently asked questions
Can I recover if I was 50% at fault in a Montana crash?
Yes, under the current operative § 27-1-702 rule. Because Montana uses “not greater than” language, an equal 50/50 allocation ordinarily permits recovery reduced by the claimant's 50% negligence.
What if I was 51% at fault?
If claimant negligence is greater than the opposing negligence used for the statutory comparison, the negligence recovery ordinarily is barred.
What if two drivers were negligent?
For the § 27-1-702 recovery threshold, Montana compares claimant negligence to the combined negligence of concurrent defendants against whom recovery is sought. Section 27-1-703 then separately governs each defendant's payment responsibility.
Can a defendant blame somebody who was never sued?
Not without regard to current § 27-1-703. Montana's statute restricts fault allocation to absent persons and contains joinder rules. Settled or released persons receive separate statutory treatment.
What happens if I already settled with one responsible driver?
The settled person's conduct can still be considered in the later fault allocation, and the remaining claim can be reduced by the percentage ultimately attributed to that person.
Does violating a traffic law mean that driver is automatically 100% liable?
No. Montana's Reed, Giambra, Tonner and Fahrnow line demonstrates that negligence per se does not ordinarily eliminate causally relevant comparative negligence by another participant.
If I had the right of way, can I still receive some fault?
Potentially. Tonner illustrates that right-of-way rules are important, but a favored driver still may have duties such as maintaining an adequate lookout and operating reasonably under the circumstances.
Does a rear-end crash automatically make the following driver 100% at fault?
No categorical Montana rule should be stated that broadly. The crash configuration is important evidence, but causally relevant conduct of both participants must be analyzed.
Is the insurance adjuster's 80/20 determination legally binding?
No. It is an insurer's claim evaluation. Civil fault remains subject to the evidence, Montana law, settlement and, if disputed, the factfinder.
Does a traffic ticket decide civil fault?
No. A statutory violation may be relevant or may establish negligence per se, but civil liability still requires causation and comparative analysis.
Can failure to wear a seat belt reduce a Montana crash recovery?
MCA § 61-13-106 expressly provides that seat-belt nonuse is not admissible in the covered civil motor-vehicle action and does not constitute negligence.
Why is Fahrnow important?
Fahrnow is a recent Montana Supreme Court vehicle case emphasizing that when evidence reasonably supports negligent conduct on both sides, comparative negligence ordinarily belongs to the factfinder rather than being converted into a one-sided summary judgment.
Do not start with a percentage. Start with the evidence.
Reconstruct the crash. Identify each negligent act. Prove causation. Identify every legally relevant responsible person. Join appropriate tortfeasors. Account for settlements and releases. Then apply Montana's 50-percent threshold, reduce damages for claimant negligence, and use current § 27-1-703 to determine each defendant's payment responsibility.