The majority of new passenger vehicles sold in the United States include some combination of automatic emergency braking, lane departure warning, lane keep assist, adaptive cruise control, and blind-spot monitoring as standard or common optional equipment. These systems were marketed as safety enhancements, and in aggregate they have reduced certain collision types. They have also created a new category of crash: one where the driver relied on the system's advertised capability, the system failed to perform as a reasonable consumer would expect, and the crash resulted from that gap between marketed capability and actual system behavior.
When the system failure contributed to the crash, a product defect claim against the vehicle manufacturer runs alongside the standard negligence case. Both claims require their own investigation and expert support, and they may name different defendants. The general negligence case in auto accident litigation proceeds against the at-fault driver; the product defect claim proceeds against the vehicle manufacturer and may also name the ADAS system component supplier if the defective system was a third-party module installed by the manufacturer.
SAE Automation Levels and What They Mean for Liability
SAE International's automation taxonomy classifies driving automation from Level 0 (no automation) through Level 5 (full automation). Level 1 systems assist the driver with a single function such as adaptive cruise control. Level 2 systems automate steering and speed simultaneously but require the driver to remain attentive and in control. Virtually all ADAS systems in standard consumer vehicles sold today are Level 1 or Level 2. The driver remains legally responsible for monitoring the road and overriding the system when conditions require.
The liability implication is that a Level 2 system failure does not eliminate driver negligence; the driver should have maintained attention and overridden the system. But the failure of the system to perform within its advertised operational envelope creates a concurrent product defect theory, and the factual question for the jury is whether the system's behavior was a defect that contributed to the crash regardless of the driver's own conduct.
Key ADAS Systems and Their Failure Modes
Automatic emergency braking systems can fail to activate in foreseeable collision scenarios, can activate inappropriately causing rear-end crashes by following vehicles, or can activate partially without sufficient force to prevent the collision. AEB failure documentation typically requires the event data recorder and the vehicle's active safety system logs, which are separate from the standard EDR crashworthiness data.
Lane keep assist systems can fail by not detecting lane markings in adverse weather or road conditions, by counter-steering into an obstruction, or by overriding the driver's steering input at a critical moment. Blind-spot monitoring systems can fail to detect motorcycles, cyclists, or narrow vehicles because of radar cross-section limitations that were known to the manufacturer during development. Each failure mode has a specific set of engineering records and manufacturer development documents that are the discovery target.
The Product Defect Theory
A design defect claim against the manufacturer argues that the ADAS system's performance in the specific crash scenario was below the level that a reasonably safe design would provide, and that a feasible safer design existed. This includes scenarios where the system was not designed to handle a foreseeable environmental condition, such as wet road lines, unusual lighting, or object types that were known during system development to be challenging for the sensor array. Under the risk-utility test, the probability of the failure type multiplied by the severity of the resulting injury, compared to the cost of the safer design, is the analytical framework the expert must address.
A failure-to-warn defect theory is also available in ADAS cases: if the system's limitations in specific conditions were known to the manufacturer but were not adequately communicated to the consumer in the owner's manual or through the system's own interface, the failure to warn about those limitations is an independent basis for defect liability. Marketing materials that implied broader capability than the system could deliver are relevant to the failure-to-warn theory and to the consumer expectation test.
Evidence: Event Data and Engineering Records
The vehicle's event data recorder contains pre-crash speed, braking, steering, and in some vehicles ADAS engagement status in the seconds before impact. The ADAS-specific operational data logs, if present in the vehicle's onboard diagnostic system, may show whether the specific system was active, what the system commanded in the moments before the crash, and whether any fault codes were logged. Preserve the vehicle before it is repaired or inspected by the defendant manufacturer's expert team.
NHTSA's special crash investigation database includes published reports on specific ADAS-involved crash events, and NHTSA's Standing General Order for automatic emergency braking and advanced driver assistance system crashes requires manufacturers to report detailed information on crashes involving those systems. That regulatory data is publicly available and can establish whether the specific failure mode in your client's case has been documented in prior events that the manufacturer was aware of.
Expert Requirements
An automotive safety engineer or human factors expert with ADAS system expertise is required to address the design defect theory. The expert should have familiarity with the specific sensor technology (camera, radar, LiDAR, or a combination) used in the vehicle at issue, the relevant SAE standards and ISO 26262 functional safety requirements that govern ADAS development, and the specific literature on the known failure modes for that system type. For product liability claims against vehicle manufacturers, the ADAS defect case benefits from an expert who has worked within the automotive development context and can address the manufacturer's internal design decision record with technical specificity rather than purely academic credentials.