In recon, we operate in a world of ranges stacked on ranges. How fast was a motorcycle going that skidded for 50 feet, capsized, slid for 40 feet, and finally hit the side of a pickup? There’ll be a decel range for the braking phase, a decel range for the sliding phase, and usually a hefty range for the impact speed. This week’s installment is about a popular method for analyzing the interaction of such parameters.

The Monte Carlo method

No, not like a Chevy…it’s a simulation/calculation method that was originally developed under secrecy at Los Alamos, therefore requiring a code name which was reportedly derived from the casino in Monaco. I teach this method during every motorcycle recon course and ~70% of attendees are hesitant to give it a go and ~95% are glad they did. Don’t let it intimidate you, the underlying concepts are simple, and the ever-prolific Wade Bartlett wrote this excellent SAE paper detailing a practical method that can be performed with any spreadsheet program, like Excel. The related abstract is below.

“Monte Carlo analysis has been shown to be a powerful tool for evaluating confidence limits and probability distributions for values calculated during the analysis of vehicle accidents. Using this tool has generally required specialized software. This paper presents a method of using the tools provided with most simple spreadsheet programs to conduct Monte Carlo analysis with both evenly distributed and normally distributed variables for cases where the equations can be expressed in closed form. The accuracy one can expect given a particular number of trials is discussed. Example analyses using both even-probability and normal-probability variables are shown.”

Coincidentally, the man himself (Wade) is teaching a two-hour Monte Carlo with Excel for Recons course on December 15th via NAPARS. It’s free for members and a whopping $5 for non-members. If you’d like a little Excel prep before heading in, I have a video here that could help.

Get down and dirty, give it a go...I suspect you’ll be happy to have the tool in your kit.

Lou Peck
​Lightpoint | Axiom​

P.S. Our podcast with the incredible Tim Cheek and Matt DiSogra is finally up! If you're interested in HVEDR, there's plenty to dig into here.