A driver loses consciousness, drifts across lanes, and strikes your client. The carrier's first response is familiar: the driver had a sudden medical emergency and cannot be negligent. The defense is real, it is recognized in most states, and it is also narrow. Plaintiff counsel who understand its elements and its factual weaknesses can often keep the case alive or defeat the defense at summary judgment.
What the Defense Requires
Courts treat a sudden medical emergency as an excuse for conduct that would otherwise be negligent when the driver was suddenly stricken by an incapacitating event that was unforeseeable. The key idea is that the person cannot be held to the standard of a reasonable driver if the person lost the ability to control the vehicle without warning. Jury instructions in many states reflect this, for example by asking whether the defendant suffered a sudden and unforeseeable illness or loss of consciousness that made him or her unable to operate the vehicle safely.
The elements, with variation by state, generally are:
- The driver experienced a sudden incapacitating medical event, such as a seizure, cardiac event, stroke, diabetic episode, or fainting.
- The event was unforeseeable, meaning the driver had no prior warning and no reason to anticipate it.
- The incapacity caused the loss of control and the collision.
The defendant usually bears the burden of proving the defense, as an affirmative defense or as a rebuttal to the presumption of negligence in some jurisdictions. Check who carries the burden in your state, as that shapes discovery and the instruction conference.
The Foreseeability Attack
Foreseeability is where most of these defenses fail. A driver who knew of a medical condition that could cause sudden incapacity, and drove anyway, may be negligent in deciding to drive. The negligence then lies in getting behind the wheel, not in the moment of the crash. Evidence relevant to foreseeability includes:
- Prior episodes of the same condition, including earlier blackouts, seizures, or near-misses while driving.
- A medical diagnosis and a physician's driving restrictions or warnings.
- Medication changes, missed doses, or skipped insulin or anti-seizure medication.
- Symptoms earlier that day, such as dizziness, chest pain, vision changes, or fatigue.
- Reports to the state licensing agency, and any medical review or restriction on the license.
Obtain the driver's medical records through discovery, subject to privilege rules and protective orders. Many states treat the physician-patient privilege as waived when the defendant puts health in issue by asserting the defense. Move promptly to compel records if the carrier asserts the defense but resists producing the medical history that supports it.
The Causation Question
A medical event does not automatically explain the collision. Examine whether the event actually preceded the loss of control. Event data recorder information can show whether the driver braked, steered, or accelerated before the impact, which suggests consciousness. A reconstruction expert can compare the vehicle's path with what a seizure or loss of consciousness would produce. Surveillance video, witness statements, and 911 audio may reveal a driver who was alert and distracted rather than incapacitated.
In some cases the driver claims a medical event after the fact, to avoid fault. Emergency medical records from the scene and hospital can establish what was found: whether the driver was unconscious, whether glucose or toxicology results were abnormal, and what diagnosis was made. Pay attention to inconsistencies between the driver's account and the paramedic's report. Our auto accident coverage reviews EDR evidence in more detail.
Partial Incapacity and Warning Signs
Courts distinguish complete loss of consciousness from partial impairment. A driver who becomes drowsy, lightheaded, or confused before the crash is not suddenly incapacitated; the driver has an opportunity to pull over. A fatigue-related episode is usually not a medical emergency within the doctrine, since drivers are expected to heed the warning signs of falling asleep. Establish the timeline: when symptoms started, whether they were noticed, and what the driver did in response.
Insurance and Related Defendants
The defense affects coverage questions less than liability, since most auto policies pay for accidents caused by a driver's medical event. If liability is excused, though, the plaintiff's recovery may depend on other sources: UM or UIM coverage for those injured by someone not legally at fault does not generally apply, because those coverages typically require legal entitlement to recover from the other driver. First-party med-pay, discussed in our auto accident category, may be the most reliable payer.
Look for additional defendants. A prescribing physician who failed to warn a patient about driving risks can be a defendant in some states, an employer who required a driver with a known condition to operate a vehicle may share responsibility, and a vehicle owner who entrusted the vehicle to someone with a known condition may face negligent entrustment claims. When the driver was commercial, regulatory standards for medical fitness may apply, as discussed in our trucking coverage.
Strategy
- Request the defense of sudden emergency in interrogatories and require facts.
- Move early for the driver's medical and licensing records.
- Retain a medical expert, often a neurologist or cardiologist, to evaluate the plausibility of the event and its warning signs.
- Preserve EDR data, scene video, and EMS records.
- Brief the burden of proof and the instruction well before trial.