Traffic Liablity

How fast was the vehicle traveling? Was there sufficient time for the driver to avoid the collision? Was the driver wearing his/or her seatbelt and if not, would the seatbelt have prevented his/her injuries? The airbags did not deploy in the collision, was it because the airbags did not function properly? Two vehicles collided in the intersection – who ran the red light? Does the paint transfer deposited on the vehicle match up with the paint on the alleged hit and run vehicle? Were the roadway conditions (lighting, signage, configuration) contributory factors to the collision?

These are some of the typical questions that NBI’s accident reconstruction and biomechanics experts assess in cases with disputed liability. Our team of experts collects and analyzes the available physical evidence and apply scientific techniques to determine how collisions and injuries occur. No two accidents are exactly the same, but we follow peer-reviewed and industry-accepted scientific methods to develop expert opinions about liability in cases. If there is limited physical evidence, we consider all possible scenarios and evaluate the likelihood of each before reaching conclusions with reasonable probability. NBI’s experts regularly conducts case-specific testing related to vehicle performance and vehicle crashes to study the response of components, occupants, and vehicles under various conditions. This allows NBI experts to understand the physics and science unique to the case we are investigating.

Intersection collisions are a common type of liability-disputed case that NBI experts investigate. It may involve one vehicle initiating a left turn in the path of the other vehicle, or two vehicles involved in a broadside collision, with both parties providing conflicting testimony about sequence of events and claiming to have entered on a green light. In these instances, an accident reconstruction is first required to determine the speed that the involved vehicles were traveling at the time of collision. This can be done with a momentum analysis, considering the vehicle trajectories post-collision, and a crush analysis, by calculating the force and energy required to deform the involved vehicles. These analytical techniques involve scrutinizing photographs taken at the scene for physical evidence (i.e. vehicle rest positions, tire marks, gouges, fluid trails, damage patterns to vehicles, debris) and determining their locations, performing physics-based validated computer simulations that is consistent with the physical evidence, and determining crush measurements through vehicle inspections or photogrammetry techniques.

Sometimes, impact speeds can provide information about which party is more likely to have entered the intersection on a red light, based on physical limitations of vehicles and inconsistencies in statements. A time-distance analysis is usually performed by our accident reconstruction experts to assess the relative positions between the vehicles, where sightlines and avoidance opportunities can be evaluated.

Recent technologies have allowed for a proliferation of digital data to be retrieved from modern vehicles, including airbag control modules, in-vehicle infotainment and telematics systems, and dealer tools. For example, airbag modules can record crash-related data (prior to and during a collision). Infotainment systems store data from cell phones connected to vehicles and navigation. For select vehicles, dealer tools can be used to image data recorded from events not triggered by crashes (i.e. sudden braking, steering, acceleration). NBI’s accident reconstruction experts are experienced in retrieving and interpreting these forms of digital data, which can assist in in the analysis of determining “what happened” and provide insight on “why it happened”.

Leading Expert

Felix Lee, MS, PE