Previously, we covered a case study where we analyzed a crash scene based on photographs to show our readers the concept of photogrammetry. The crash scene included roadway evidence that is usually found after a crash occurs – namely skid marks, gouges, roadway damage, those kinds of things. We often get asked many questions related to the analysis that we can provide based on photographs alone.
It is becoming more and more common for analysis to take place after the fact, when only photographs of the accident are available and any physical evidence related to the crash is long gone. After a while, skid marks on the road will fade to nothing, and the vehicles involved may not be available for us to inspect anymore (usually they are disposed of or recycled after a couple months or less). So, what if the vehicles are gone? What can be done?
To answer these questions, I’ve created this case study showing our analysis of vehicle damage based only on photographs. This is a powerful method that allows us to come up with numerical numbers for vehicle damage that can be related to vehicle impact speeds and severity. The types of topics that are important during litigation of a car crash.
Here’s the scenario: we have a rear-end crash that involved two vehicles. The driver of the front vehicle is claiming severe injuries from the crash and was stopped when the crash happened. We only have photographs of the rear vehicle but we know the year, make, and model for both vehicles. How can we determine the impact speeds based on photographs for only the rear vehicle? Using photogrammetry, vehicle crush depth was determined:
Crash damage to rear vehicle:
Photogrammetric analysis of vehicle crush:
3D representation of vehicle crush:
Based on the photogrammetry, the vehicle crush was found to be 2 inches on the driver’s side of the front end, up to 38 inches on the right side. Correlating vehicle crush to impact speed using stiffness calculations, it was determined that the rear vehicle was traveling 55 mph, causing a delta-V of approximately 28 mph to the car in front.
This delta-V is consistent with published values of severe impacts, and may be sufficient to quantify the driver’s injuries. Granted, this scenario is hypothetical but the process is used by Veritech Engineers on many crashes with amazing accuracy. If you have questions about this approach, please contact us today. Stay Safe!