Idaho's rule: barred at 50%, against this defendant
Under Idaho Code § 6-801, contributory negligence does not bar recovery as long as the claimant's negligence was not as great as the negligence of the person against whom recovery is sought — meaning a claimant can recover only if their fault is strictly less than 50% against that specific party. Damages allowed are then diminished in proportion to the claimant's own fault.
The genuinely distinctive part: the individual rule
With multiple defendants, Idaho applies what's known as the individual rule. Rather than comparing the claimant's fault to the combined, aggregate fault of every defendant together, Idaho compares it to each defendant individually. A claimant can only recover against a specific defendant if that defendant's own share of fault exceeds the claimant's — not simply if the defendants' total fault, added together, exceeds the claimant's.
Why this matters: a worked example
Suppose a claimant is found 40% at fault, and two defendants are found 35% and 25% at fault respectively. The two defendants' combined fault (60%) clearly exceeds the claimant's 40%. But under Idaho's individual rule, the claimant cannot recover against either defendant separately, because neither individual share (35% or 25%) exceeds the claimant's own 40%. This produces a genuinely different, often harsher, outcome than an aggregate-comparison state like Connecticut or Hawaii would reach on the identical facts.
An exception for vicarious liability
The individual rule does not apply where one defendant is vicariously liable for another defendant's negligence — an employer held responsible for an employee's actions, for example. In that situation, the vicariously liable defendant's responsibility is tied to the underlying negligent party's share, rather than being treated as a separate, independent percentage.
Joint and several liability: limited, not eliminated
Idaho has also limited the old common-law doctrine of joint and several liability to a specific, listed set of causes of action. Outside those listed situations, each defendant whose fault exceeds the claimant's generally owes only their own proportionate share of the total damages, rather than being on the hook for the whole amount.