Last week, I had the pleasure of attending Mark Crouch and Stephen Cash’s Video Analysis in Collision Reconstruction course. I walked away with 20 pages of notes and many key takeaways, including the topic of this week’s edition.

The instructors consistently emphasized the importance of using the calculated dynamics of the subject vehicle to assist with your frame timing analysis. Don't forget to bring your collision reconstruction knowledge to the table. You know a 1978 Ford Pinto can’t brake at -1.4 g’s. You know a 2020 Chevy Spark can’t go from 35 to 45 mph in 0.2 seconds. By breaking the analysis down into smaller intervals, you can evaluate the timing validity by looking for nonsensical accelerations.

When you put this method into practice (it's worth experimenting to see it in action), you quickly find small changes in timing make big changes in the resultant accelerations. As such, if the vehicle positions have been accurately established and the speed trace makes sense, you’ve probably got the frame timing nailed. Mark talks more about the idea here.

So, how do you establish vehicle positions? This edition of To the Point discussed the practical photogrammetric methods. But, if you want to see them applied, I’ll be hosting a two-hour webinar next month where we’ll analyze real-world surveillance videos to determine speed using nearly every practical method.

Images from the testing that forms the foundation for the upcoming webinar.

We’ll talk about the strengths and weaknesses of each technique and compare the results to on-board instrumentation so we can quantify their performance. Topics will include frame timing, lightboards, video analysis tools, photogrammetry methods / software, and how to use scanner data in these analyses. Registration details are here if you’d like to join in on the fun.

Thanks for reading, keep exploring!

Lou Peck
​Lightpoint | Axiom