Highway Barrier Impact Analysis
Nathan Rose: Often times, we are asked to analyze how a vehicle interacted with a highway barrier. We can think of them in three general categories. One would be cable barrier. Another would be w-beam guardrail. And then, finally, concrete center median barrier or concrete barrier off the side of the road. And the difference between these types of barriers really comes down to how much they deform when a vehicle impacts them.
Barriers are there to protect people. The challenge is that there are a lot of competing issues that come into play. So, for example, we may want to prevent a vehicle from crossing over on the highway into oncoming traffic and we can successfully do that, let’s say, with a concrete center median barrier. The challenge is that the barrier is very rigid and so the rigidity of that barrier increases the injury potential for the occupants of the car that strikes that barrier.
In this type of crash there are five factors that we look at. One is the speed of the vehicle at the time it impacts the barrier. Another is the weight of the vehicle and the weight distribution of the vehicle. Another is the orientation and the travel direction of the vehicle at the time it strikes the barrier. And then, the front end geometry of the vehicle in relationship to the barrier system. And finally, we look at, in excruciating detail, the motion of the vehicle as it interacts with the barrier.
So, all these factors we’re talking about are important to understanding how the vehicle interacted with the barrier system and are important to uncovering the story that the physical evidence tells on any given case.