Measuring Security Driver Competence – The Friction Circle

Image of a friction circle

The Friction Circle is a simple and graphic method of measuring a driver’s level of competence in any vehicle in any scenario. Via an APP or on-board computer, the driver’s skill level can be measured and displayed in a graph.

Using the Friction Circle as a Measure of Driver Competence

A great deal of research has been done and data collected on the minimum standards that define a driver’s capability and skill. These studies are conducted by the Society of Automotive Engineers (SAE) and prestigious universities. The result of this research is the advancements that have been made in measuring driving skills and therefore survivability in an emergency situation.

The research defines driving skill as the driver’s “ability” to use the vehicle’s “capability.”  The graph created by driving the Friction Circle displays the forces a driver places on a vehicle during braking, cornering, acceleration, braking and cornering, and acceleration and cornering. These forces and the drivers level of competence can be measured with an inexpensive on-board computer or mathematical analysis.

Consider the Friction Circle as a Target

Consider the friction circle the same as a target in a shooting program; it is a method of measuring competence. A shooting instructor would not conduct a shooting program without targets; basically, without some method of measuring competence.

However, there are many Security Driving training programs that conduct training with no means of measuring the student/driver’s competence; they have no target. Also, there are many “Security Drivers” in the field that have never had their driving skill measured. It is equivalent to having an EP agent with a weapon, but the agent has never fired a weapon at a target.

Training – “We Don’t Need No Stinking Targets”

Would you attend a shooting program where the instructor says, “We don’t need targets? I have been teaching many years, and I can tell by the way you hold the weapon that you are a competent shooter. We don’t need no stinking targets.” That would be ridiculous. The same holds true for Driver Training; Don’t attend a driver training program that does not measure your ability to use the vehicle’s capability (competence), either via mathematical analysis or on-board computer or both. In fact, you should not attend any training where there are no goals – standards to achieve – where there is no “target”.

Will You Ever Drive the Friction Circle?

Keep in mind that if a problem occurs, accident or ambush, YOU WILL DRIVE THE FRICTION CIRCLE.

It is not a question of if, you may, or could possibly drive the friction circle. When stuff happens, you WILL drive the friction circle, whether you want to or not. The principals and your life depend on how you perform in the friction circle. – WHO IS DRIVING YOUR PRINCIPAL

Tony Quiroga, a writer for Car and Driver did an article on the Friction Circle. In my opinion, he is one of the better automotive journalists. His opening remarks says it all:

“Driving successfully at a car’s limits is less about bravery and more about understanding the dynamics of three disciplines—acceleration, braking, and cornering—and how they work together.”

The time to find out how good you are working the circle is not when you’re neck deep in sh*t.


About the International Security Driver Association

The International Security Driver Association (ISDA) serves the Protective Services community. ISDA’s mission is to support an international forum of protective service providers who share knowledge for the purpose of enhancing the profession.

The most common question we at ISDA get asked is, “Is ISDA for Security Drivers and Secure Transportation Providers only?” The answer is a big NO. ISDA is a valuable resource for all practitioners working in the protection profession. Members of ISDA represent all facets and levels of the protective services profession as an example.

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