Heavy Truck Crash Reconstruction
Heavy Truck Crash Reconstruction: Over time, physical evidence like tire marks, debris and gouges in the road can fade and deteriorate making the evidence gathering process more difficult. Nathan Rose received a call about this collision just days after it occurred. Having a chance to review the site quickly gave profound insight and provided key evidence that was used to reconstruct the crash, which was caused by a heavy truck crossing the center line of a highway. In this heavy truck crash reconstruction case study, Nathan, along with Neal Carter and Tomas Owens, discuss how physical evidence, along with electronic data from the vehicles, was used to reconstruct this crash into a full simulation animation.
[Various News Media]
[Nathan Rose]: The client called us shortly after the crash occurred. It’s a case that involved a heavy truck driver who, according to witnesses, was swerving into oncoming traffic in the couple miles preceding this accident. Ultimately, the truck driver, as he went around a right-hand curve, failed to negotiate that curve, went into oncoming traffic and collided with two vehicles, one in a very severe manner.
We were out at the site within a few days of this accident happening and that really helped a lot in our investigation. I mean, you can imagine that being out there a few days after there’s a lot of evidence still in place that we’re able to physically document. We were able to see the vehicles as well in a very short time frame after the crash and to get those documented with 3D laser scanners. So, we’re able to capture that data and preserve it before there’s any modifications to it.
[Neal Carter]: So, event data recorders on vehicles, they were starting to become more and more common. This is the first one in memory where we actually had an event data recorder on each vehicle. So, on the tractor-trailer, on the pickup and on the van. So, that was great from an engineering perspective. We had the tractor-trailer give us about 100 seconds of data before the crash and about 15 seconds after the crash. In the 100 seconds before we were able to see where, for instance, hilltops were because we’d see the speed decrease. So, we were able to correlate that with the driver’s route before the crash and it really confirmed that that speed data was from this crash. The best witnesses in this crash were the event data recorders on the vehicles.
[Tomas Owens]: In a case like this, we utilize photogrammetry to give us an idea of where the locations of these pieces of evidence lie, whether that’s debris, the vehicles’ final resting place; a lot of the key components that are involved with the physics and the motion of the action itself.
[Neal]: We had the restraints of the event recorder data of all the vehicles and we had to make that mesh well with out simulation, mesh well with the physical evidence that was on the roadway, and mesh well with the rest positions of all the vehicles.
[Tomas]: One of the challenges involved with a case like this, when there is such a high amount of debris and impacts, could be cleaning up the images to make it visually acceptable for an animation.
[Nathan]: So we have a number of animations we created in this case where we are animating the accident over the top of a police photograph. So, part of that process is determining the positions from where that photograph was taken and you’ll see that in some of the animations that we play in this case study where it’s over the top of a police photograph.
[Tomas]: When we’re going to use an image, a lot more time and effort has to be spent cleaning up these images to make them visually appealing as well as the conditions that the road was at prior to the accident. Some of the other key factors involved in an animation going beyond impact would be simulating the vehicles to rest. That can be sort of a rocking or rolling motion as the vehicle comes down. Some of that is given to us, in part, by the engineers and through simulation software that gives us a realistic representation of how something this heavy and this big that has been damaged this much would realistically roll across the environment.
[Nathan]: We utilized PC Crash simulation software to generate physics-based motion for the vehicles and that motion goes directly into our animation. So, what we end up with is an animation that is physics based, and that accurately portrays the motion of those vehicles based on the data we have and based on the reconstruction we’ve done. So, the motion you’re watching in these animations in this case study is all physics based and it’s all justified by the physical evidence.
We want to make sure that we build our animations in a way that they are admissible when we get to that point of going to trial. And so, part of that process, part of what lays the foundation for an animation’s admissibility is us being able to show that what we’re depicting is physically realistic and justified by the evidence. And so, that guarantees that when we get to the end of this process we’re going to have a product that a judge is going look at and accept into a trial.