The Science of Surveillance Detection and Security Driving


A while back, I was asked to do lessons learned from a vehicle ambush. It was a two-car scenario, with both cars taking some hits but no injuries. The company wanted to know why these two drivers were able to drive out of this; these are their words, not mine, “with relative ease”.

We went to the scene of the attack with the two drivers and asked them what they saw when they saw it and where they were when they saw it. My conclusion was that the driver of the principal’s car had a 1 to 1.5-second jump on the incident; he was 1.5 seconds ahead of the ambush.

My educated guess is that if these drivers had delayed their action by .5 to 1 second that these two guys would not be standing on a street corner talking to the gringo. The question is, what gave them the “extra” time?

To answer that question, we need to look at the science of reaction time. According to scientists who have done an enormous amount of research on driver reaction time, the “average” driver needs 2.5 seconds from the time they see the problem to the time they react to the problem. Dr. Green has been researching reaction time for years if interested in the science of reaction time, Google his name. Here is a small part of what he found;

Condition A – When drivers know they have to brake, they can achieve the best possible reaction time. Dr. Green’s research shows that the best estimate is 0.7 seconds. Of this, 0.5 is perception, and 0.2 is movement, the time required to release the accelerator and depress the brake pedal.

Condition B – When the need to brake is a complete surprise, reaction time is substantially different. In this case, Dr. Green suggests that the best estimate is 1.5 seconds for something that may be coming at you from the side (This attack came from the side) and a few tenths of a second faster for straight-ahead obstacles.

What does all this science stuff have to do with Surveillance Detection? A good SD program trains you to recognize pre-incident indicators and to identify danger zones. If, by attending a good SD training program, you are in Condition A – you have an extra .5 to 1 second additional time to react to the problem. In the case of my two drivers, according to my calculations, it gave them an extra 26 to 52 feet, enough for them to drive out of the problem.

A point of interest – these reaction time numbers are valid when walking with the Principal 

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