Evidence in Serious or Fatal Semi-Truck Crashes or Car Accidents: What is Crush Analysis?

Accident reconstructionists can be invaluable to accident victims who have the legal burden of proving their case against those responsible for the crash, because they can do an expert crush analysis.

The risk of being involved in a catastrophic or deadly car accident, semi-truck crash, or motorcycle accident is particularly high here in Illinois and Indiana. Not only do we have more commercial truck traffic than many other parts of the country, but we have complications like extensive road work construction zones, notorious winter weather conditions, and other hazards that increase the likelihood of a motor vehicle accident. For more, read Traffic Fatalities in Chicagoland: High Risk of Deadly Chicago Car Crash; and Huge and Growing Freight Truck Traffic in Northern Indiana: Increasing Danger of Semi-Truck Crashes.

When someone suffers harm in a roadway collision, that accident victim and their loved ones have the legal right to independently investigate the incident to determine if one or more parties have legal responsibility for what happened. Civil claims may exist under state laws like driver negligence; product liability; premises liability; negligent hiring, supervision or training; and more. See, Semi-Truck Crashes in Chicago: When are Trucking Companies Liable for Big Rig Accidents? Negligent Supervision by the Trucking Company and Semi-Truck Crash; and High Number of Fatal Car Accidents in Indiana and Illinois: Protecting Yourself and Your Loved Ones.

The accident victim has the legal burden to prove their claims for damages with authenticated and admissible evidence. Their legal advocate or law firm helps in building their case. However, in serious collisions the victim will need the help of professional experts (think engineers) who analyze the facts involved in the event to explain how it happened.

The lawyer and the injury victim will both look to accident reconstruction experts to use a variety of evidence so they can analyze and determine the causes and circumstances of their crash. One of the most important functions of these accident experts is the crush analysis.

What is Crush Analysis After an Car Accident or Truck Crash in Illinois or Indiana?

After an accident, professionals in accident reconstruction are able to figure the speed and trajectory of all those involved in a specific incident by using things like the energy absorbed into each vehicle during and after impact and comparing them to undamaged vehicles of similar type, size, age, etc., finding the “crush volume.” From this, they are able to provide expert opinions as to the causes of the collision and who or what was possibly at fault for the truck crash or car accident.

See, Sharma, Sanyam, Anoop Chawla, and Sudipto Mukherjee. “Investigation of Real-World Crash Using an Accident Reconstruction Methodology Employing Crash Test Data.” SAE International Journal of Advances and Current Practices in Mobility 6.2024-26-0288 (2024), where researchers explain:

The objective of vehicle crash reconstruction is to determine the vehicle’s motion before, during, and after the crash, as well as the impact on occupants in terms of injuries. Simulation approaches … have been developed to understand pre-crash and post-crash vehicle motion, rather than the crash phase behavior.

How Crush Analysis Works In Accident Claims

Working together as a team, the legal advocate for the accident victim; the injured person and their loved ones; and the accident reconstruction expert will gather all the facts needed for the final crush analysis. It may be a very complicated and time-consuming process just to gather everything that is needed for a proper crush analysis to be done.

The injured person can provide memories and explanations from that day (or night). This may involve not only the crash itself but what was going on prior to it: the traffic conditions, if there were potholes in the roadway, what the weather was like; etc.
Their lawyer will use procedural rules of discovery to find facts in things like witness statements; video recordings from dashcams and nearby security cameras; photographs and other details from the police reports; and even the recollections of the defendants through things like depositions or requests for written information.
The accident reconstruction expert will come with special equipment, such as cameras to take high-resolution photos; three-dimensional scanners; plumb bobs; and special software for calculation of things like stiffness coefficients and kinetic energy loss.

For more, read: Accident Reconstruction Experts and Injury Claims; and What To Look For in a Personal Injury Lawyer in Indiana or Illinois.

Crush Analysis Calculations

After assembling all the facts that can be found, the accident reconstructionist expert brings critical knowledge to the job. For instance, they understand things like how tractor-trailers and other large trucks are built differently, according to their function. Semi-trucks always have stiffer frames because of the weight they must carry; accordingly, they will suffer less crumpling in a crash than a smaller motor vehicle, like a minivan or SUV.

Their calculations will be intricate and extensive. It will be a joint effort by both the victim’s lawyer and the reconstructionist to clearly explain things to a jury such as average crush depth; stiffness coefficients; energy absorption in foot-pounds; vehicle mass in slugs; and speed using the kinetic energy formula.

Outside research will come into play here, too, which will need to pass muster with the evidence rules to be included in the jury’s deliberations of the expert opinion. For instance, crash data from the National Highway Traffic Safety Administration may be used in the expert’s determination of how the victim’s car absorbed energy during the crash impact.

Another Factor in Crush Analysis: Type of Accident Changes Things

In addition to the calculations involving the impact itself, the reconstructionist will need to consider the type of accident involved. Was the victim involved in a rear-end collision? Was there an underride crash with a tractor-trailer truck or a reefer? Did the accident involve multiple crashes, with secondary collisions?

Computer simulations may be done using proprietary software operated by the reconstruction expert. Biomechanics come into play, too. There may be expert opinions from these experts on how the force of impact affected the various victims (things like at what speed of trajectory, etc.) and how this caused harm to the human bodies.

See: Daily, Jeremy, Russell Strickland, and John Daily. “Crush analysis with under-rides and the coefficient of restitution.” Proceedings of the 24th Annual Special Problems in Traffic Crash Reconstruction (2006) and Mokhtar, Abdul Ahad, and Ludek Hyncik. “A comprehensive review of human body model in different crash scenarios: active and passive models.” International Journal of Crashworthiness 30.1 (2025): 1-13.

Crush Analysis Expert Opinion: Meeting the Victim’s Burden of Proof in Injury Claim

After the expert opinion has been completed, it can be formalized into a report that can be used by the accident victim to help demonstrate the reasons for their injuries and what caused them. These facts can then be dovetailed with the legal research and arguments of their attorney to establish they have met their legal burden of proving that the defendants are liable for the event that resulted in the victim’s harm.

While the expert was not involved in or witness to the accident, the reconstructionist can explain the facts of that crash in ways that others cannot. Crush analysis must be done by experts in their field. There are times, especially after particularly tragic and deadly collisions, where their efforts are invaluable in explaining what happened and supporting the victim’s legal claims.

For more, read:

Accident victims and their loved ones may have legal redress against those whose actions or failures to act caused their harm, but it may take the help of a professional accident reconstruction expert to find justice. Please be careful out there!