Authored by Kelly Bosch, Ph.D., P.E., ACTAR, Principal Consultant.
Published on May 14, 2026.
A Forensic Expert’s Guide to Airbag Non-Deployment Analysis
When an airbag does not deploy during a vehicle accident, it can raise critical questions:
- Why didn’t the airbag deploy or inflate?
- Should the airbag have deployed based on the severity of the crash?
- Was the system functioning as designed, or was there a failure?
- Was this a counterfeit airbag?
These questions often cannot be answered by vehicle inspection alone. A reliable airbag investigation requires an integrated evaluation of crash dynamics, occupant motion, and injury biomechanics, as well as an understanding of airbag deployment algorithms and their limitations.
These cases often involve airbag non-deployment analysis, airbag failure investigation, and counterfeit airbag identification, requiring coordination between biomechanics experts and accident reconstruction specialists. Our consultants evaluate whether an airbag should have deployed and whether the system performed as designed under real-world crash conditions.
Airbag systems are engineered to deploy only when specific crash thresholds are met. Determining if thresholds were reached requires an accident reconstruction, along with an understanding of vehicle crash sensors and deployment algorithms. Injury biomechanics also provides essential insight into whether the injuries sustained are consistent with the reported collision and the expected performance of the restraint systems.
What Does an Airbag Investigation Include?
- Airbag non-deployment analysis and deployment threshold evaluation
- Counterfeit or non-OEM airbag identification
- Airbag control module (ACM) and electronic data recorder (EDR) analysis
- Accident reconstruction and delta-V assessment
- Occupant kinematics and injury biomechanics evaluation
- Seat belt use and restraint system performance analysis
- Injury consistency with reported crash conditions
Learn more from Dr. Kelly Bosch, a Rimkus biomechanics expert, in her Q&A blog post here.
Linking Injury Consistency to Occupant Kinematics and Crash Severity
In airbag non-deployment cases, injury patterns often tell a critical part of the story. Rimkus biomechanical consultants evaluate injury consistency by examining how the occupant’s body moved during the collision and how that motion aligns with the vehicle damage and crash forces. An important step to perform is occcupant kinematics analysis, which focuses on body position, restraint use, and movement before, during, and after impact to help determine whether airbag deployment would have been expected to alter the injury outcome.
Occupant biomechanics and injury biomechanics analysis allow us to assess whether injuries are consistent with the event, and the absence of airbag deployment. Examining the occupant biomechanics can also provide insight as to the occupant’s position in the vehicle at the time of a collision, for example if there is a dispute on seating positions or if an occupant is out of position. This approach helps distinguish between system performance questions and situations where the crash conditions did not warrant airbag deployment.
The Role of EDR Downloads in Airbag Investigations
Electronic data recorder (EDR) downloads are a key component of many airbag investigations. EDR data collected from a vehicle’s airbag control module (ACM) can often provide objective information regarding vehicle speed, delta-V, braking, throttle input, seat belt usage, and airbag command status. When interpreted alongside physical evidence and injury biomechanics findings, EDR data helps establish whether deployment thresholds were met and whether airbag non-deployment aligns with the reconstructed crash scenario.
Our consultants integrate EDR downloads into the broader accident reconstruction process, ensuring that the data is evaluated within proper technical and biomechanical context. This reduces the risk of overreliance on isolated data points and supports defendable conclusions.
At times, vehicles are unavailable for download or are too old to contain ACMs that collect data. Using holistic approaches with the available information, insight into why an airbag did or did not deploy can often still be provided with an analysis of the circumstances of the accident.
A Comprehensive, One Stop Approach to Airbag Non-Deployment Analysis
Airbag investigations are most effective when accident reconstruction and injury biomechanics are evaluated together. Rimkus provides an integrated, one-stop solution that includes accident reconstruction, EDR analysis, occupant kinematics, occupant biomechanics, and injury consistency evaluation. Our methodology can determine whether an airbag should’ve deployed, why it did or didn’t deploy, and how injuries were sustained.
By focusing on injury biomechanics in transportation incidents, we can help clients reach clear conclusions in complex airbag non-deployment cases. Our experts’ comprehensive approach supports informed decision making in claims evaluation, litigation, and risk management.
Contact Rimkus
Looking for help with an airbag investigation? Contact us today to schedule a consultation.
This article is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.