Crashworthiness cases are technical. Engineers, biomechanists, accident reconstructionists, and corporate witnesses all speak in vocabulary that does not appear in everyday conversation. This glossary translates the most important terms in plain English so that injured clients, family members, and referring lawyers can understand the engineering and legal concepts that drive these cases.
Cronauer Law publishes this resource as part of our public-facing educational library. The definitions below are intended for general informational use; the controlling definitions in any given case are those used by qualified retained experts and adopted by the court.
No upfront costs & fees
Means you can afford a lawyer now
And our trial lawyer has a 7 year winning streak…
Delta-V (∆V) is the change in velocity experienced by a vehicle or occupant during a collision, expressed in miles per hour or kilometers per hour. Delta-V is the single most important number in determining how survivable a crash should have been; it is the input from which biomechanical experts evaluate whether an occupant’s injuries are consistent with proper restraint or instead suggest a defect.
Closing speed is the speed differential between two vehicles on a collision course. For opposing vehicles, it is the sum of their speeds; for vehicles traveling in the same direction, it is the difference. Closing speed is not the same as Delta-V.
The coefficient of friction is a measure of skid resistance between a tire and the roadway, expressed as a decimal value of one G of acceleration. Lower numbers indicate slicker surfaces and longer stopping distances; reconstructionists use coefficients of friction to back-calculate vehicle speed from skid evidence.
The center of mass is the imaginary point at which a rigid body’s mass is concentrated. In rollover stability analysis, the height of the vehicle’s center of gravity above the ground is one of two key inputs—along with track width—to the static stability factor that NHTSA uses to predict rollover propensity.
The Static Stability Factor is the ratio of half the track width of a vehicle’s axle to the height of its center of gravity. Lower SSF values correspond to higher rollover risk. Many SUVs and light trucks have SSF values significantly below those of passenger cars, which is why their rollover rates are higher.
Kinetic energy is the energy of motion, defined as one-half the mass of an object times the square of its velocity. Because velocity is squared, doubling crash speed quadruples the energy that the vehicle structure and restraint system must manage.
A yaw mark is a curved tire mark on a roadway surface caused by lateral slipping of a tire that is still rotating. Yaw marks are important evidence of pre-rollover loss of control and are central to many on-road stability cases.
A three-point belt is the standard combination lap-and-shoulder belt installed in modern passenger vehicles. It is anchored at three points: outboard at the floor, inboard at the floor, and at the upper D-ring on the B-pillar.
The latch plate is the metal tongue inserted into the buckle. The D-ring is the metal loop on the B-pillar through which the shoulder belt passes. Forensic markings on these components—sometimes called load marks or witness marks—are used to confirm whether the occupant was belted at the time of the collision.
A pretensioner is a pyrotechnic or mechanical device that retracts seatbelt webbing in the first milliseconds of a crash to remove slack and place the occupant in a tighter, more controlled coupling with the seat.
A load limiter, often torsion-bar or stitch-tear designs, allows the seatbelt to pay out a controlled amount of additional webbing during a high-energy event in order to limit chest loading and reduce the risk of belt-induced thoracic injury.
Inadvertent unlatching occurs when a properly latched seatbelt buckle releases during a crash event without occupant input, often as a result of inertial forces or external contact with the buckle release. False latching occurs when a buckle appears to engage but is not fully secured.
Spool-out is the unintended payout of seatbelt webbing from a retractor during a crash, resulting in the occupant becoming effectively unrestrained.
The A-pillar is the structural pillar at the windshield, the B-pillar is the central pillar between the front and rear doors, and the C-pillar is at the rear window. Pillar deformation is one of the most reliable indicators of roof crush severity in rollovers.
Survivable space is the volume of the occupant compartment that remains intact and unintruded after a collision. Maintaining survivable space is the central objective of crashworthy vehicle design.
Strength-to-weight ratio is the FMVSS 216 metric for roof strength: the load the roof can support before deforming five inches, divided by the curb weight of the vehicle. The 1971 standard required 1.5 SWR; the upgraded standard now requires 3.0 SWR for newer vehicles.
Glazing is the technical term for vehicle glass. Tempered glazing shatters into pebbles when broken; laminated glazing—a sandwich of two glass plies and a plastic interlayer—does not vacate the window plane and helps retain occupants in rollovers.
The crashworthiness doctrine is the products liability principle that holds vehicle manufacturers responsible for failing to design and build vehicles that adequately protect occupants in foreseeable crashes. The seminal case is Larsen v. General Motors Corp., 391 F.2d 495 (8th Cir. 1968).
The FMVSS are the federal minimum performance and design standards promulgated by NHTSA at 49 C.F.R. §§ 571.1–.302. The most frequently litigated FMVSS in crashworthiness cases include 208 (occupant crash protection), 209 (seatbelt assemblies), 210 (anchorages), 213 (child restraint systems), 216 (roof crush), 226 (ejection mitigation), and 301 (fuel system integrity).
A sharing protective order is a discovery order that permits plaintiffs’ counsel to share confidentially produced documents with other lawyers handling similar cases against the same defendant, subject to the order’s terms.
A Morris Inquiry is a defense discovery request, named after Morris v. Honda Motor Co., that seeks to compel a plaintiff to disclose all defendant-originated documents in plaintiff’s counsel’s possession. It is widely opposed as overbroad and as work-product invasive.
A statute of repose is a legislative bar that prevents lawsuits filed beyond a fixed period after a product is sold or delivered, regardless of when the injury occurred. Repose periods vary widely by jurisdiction.
Delta-V tells biomechanical experts how much force was transferred to the occupant. If the Delta-V was modest but the injuries were catastrophic, the discrepancy is often the strongest signal of an underlying defect in the restraint system, the roof, the fuel system, or the seat.
FMVSS are minimum standards. A vehicle can comply with every applicable FMVSS and still be defectively designed under state law. The Supreme Court confirmed this principle in Williamson v. Mazda Motor of America, Inc., 562 U.S. 323 (2011), and the Safety Act expressly preserves common-law remedies. 49 U.S.C. § 30103(e).
The static stability factor predicts the propensity of a vehicle to roll over in an emergency maneuver. Lower SSF values correlate with higher real-world rollover rates. Many narrow-track, high-center-of-gravity SUVs have notoriously low SSF values, which is one of the central liability themes in stability cases.
Spool-out describes a retractor mechanism allowing more webbing to pay out during a crash than the design contemplated. The result is effectively an unrestrained occupant. Spool-out cases turn on retractor design, sensor placement, and the manufacturer’s knowledge of similar real-world events.
Most are. A small number of terms—particularly in biomechanics and rollover dynamics—are contested between plaintiffs’ and defense experts. Cronauer Law works only with experts whose definitions and methodologies have withstood Daubert and Frye scrutiny.
Ranked top 10 in the Nation
The National Trial Lawyers recognizes Nicholas Cronauer as one of the top 10 lawyers
under the age of 40 in the nation.
With you at every step
Cronauer Law has years of experience representing clients who have been seriously injured.
We know what it takes to win, and have prepared the the steps we need to take to get the best outcome clients can expect from hiring a lawyer.
Contact us to get the process started. Our lawyers will explain the laws around your case at no cost to you.
We work with the insurance companies to ensure they fulfill their duties to cover the costs related to the crash
A Serious injury can dramatically change how you plan on reaching your life goals. We’ll work with you long after the case has won to ensure your life gets to where it needs to be
We take pride in what we do
We understand that most people may not have hired a lawyer before, so we make it as easy and clear as possible to understand what We will answer all of your questions, and guide you through this process. We are here to help you.
If you were injured in any way–medically, emotionally, physically, in a car, at work, on the street–then you may have a case. Employers, companies, and individuals have a “duty of care.” This term refers to each person’s obligation to avoid actions or situations that endanger other people.
Personal injury attorneys offer their services on what is called a “contingency fee” basis. That means we pay for all the upfront costs of your case–hiring specialists, paying court fees, even assessing medical care. You owe us nothing, and we only take a fee if you win your case.
As soon as possible, ideally. Give our personal injury law firm a call to speak with one of our staff members confidentially, even if it’s not normal business hours where you are. Also feel free to fill out our contact form with some basic information about you and your case. A member of our team will get back to you as soon as possible.
Once we’ve investigated the basic details of your injuries and your case, we’ll be able to tell you how much compensation you’re entitled to. While we (and no ethical attorney) can make promises regarding your case, we can help calculate the costs and lost wages caused by your harm.
Cronauer law injury attorneys have tried virtually every type and size of plaintiff’s claim possible. We’ve handled cases on behalf of people injured in car crashes, Engineers injured in a slip and fall, and even businessmen who have been wronged by their partners. Our firm has made a name for itself in a variety of legal areas. Our results in complex areas like commercial litigation, trucking accidents, Criminal Defense, and Product Liability barely scratch the surface. Whatever the nature of your injury, we have the experience and resources to demand compensation on your behalf.
Enter as much information as you can. Skip any questions that you do not know right away or does not apply to you.