The Science of Security Driving

The researchers express driving skill as the percentage of the vehicle a driver can use before losing control of the vehicle. If a driver can use 50% of the vehicle, they define him/her as a 50% driver, if they can use 80% of the vehicle, they are an 80% driver. The same research also has found that the average driver can only use 40% of the vehicle’s capability.

Using 80% or above of the vehicle’s capability would more than likely only happen during an emergency (accident or ambush). But what percentage of the vehicle does a Security Driver use while maneuvering through the day to day mundane chore of moving the boss from Point A to Point B, such as driving up to an intersection and slowing down – stopping at a red light – driving on an off ramp or around a corner?

To answer that question, ISDA conducted an experiment, using a G-Meter, measuring how much of the vehicle’s capability is used during normal driving routine, one absent of an emergency. What we found interesting was how little of the vehicle’s braking and cornering capacity result during the daily driving routine.

The Results
The vehicle used in the experiment was capable of .9 G’s braking and .78 G’s cornering, which means the vehicle could absorb 90% of its weight braking (.9 G’s) and 78% (.78 G’s) of its weight cornering. Keep in mind that the average driver can only use 40% of the capability of the vehicle.

As we drove up to a stop sign and applied the brakes, coming to a leisurely stop, the G Meter indicated that we used 27.8% of the vehicles capability to stop. When driving around a corner, we used an average of 28% of the vehicle’s capability. The end result is; when driving through the day to day routine, a Security Driver uses very little of the vehicle’s capability.

A Society of Automotive Engineers paper has indicated that using 30% to 35% of the capability of the vehicle is the ‘Comfort Zone’ for most drivers. If they use more of the vehicle (apply more G’s on the vehicle), the research notes that the driver gets “anxious” (The engineering way of saying scared). But if an emergency popped up a driver would instantaneously have to go well beyond their Comfort Zone and use a minimum of .8 to .9 G’s, braking or cornering to avoid the emergency.

That’s what training is about, training students to use a minimum of 80% of the vehicle and to accomplish that in a time frame measured in tenths of seconds. Basically to get drivers past their comfort zone, and (as defined by the SAE) become 80% drivers.

To put this in the context of Security Driving, a Security Driver could drive for weeks, months years and never need to drive past the comfort zone of using 40% of the vehicle. But when confronted with an emergency, accident or vehicle violence, and in the blink of an eye, the driver will need to have the ability to go past their comfort zone and use a minimum of 80% of the vehicle. But isn’t that part of the Security Drivers job description; have the measured ability to use the vehicle’s capability.

 

The Science of a Two Vehicle Scenario

The ISDA 2015 and preliminary data from the 2017 Executive/Security Vehicle Survey indicate a dramatic increase in the use of SUVs for Executive Transportation. The 2015 Survey also indicated that there had been a significant increase in the use of two car scenarios for Secure Transportation. If you couple the Survey data with the number of motorcade incidents that have occurred it points to a problem in the making.

The following is an explanation of why a two car scenario can create a risk to the principal and some suggestions on how to mitigate that risk. The risk starts with what scientists call “driver’s eye height.”

The Driver’s Eye Height
A study was conducted to assess drivers’ chosen speeds when operating a simulated vehicle, doing so while viewing the road from a low eye height (if a sedan would be the lead vehicle) and a high eye height (if a SUV would be the follow vehicle). Participants were instructed to drive, without reference to a speedometer, at a highway driving speed at which they felt comfortable and safe. Drivers seated at a high eye height (the follow vehicle) drove faster than when they were seated at a low eye height (the lead vehicle).

Consider that the majority of follow vehicles are SUV’s and that the seat in a typical SUV is about 1.6 feet higher than in a car. Apply this theory to a two car scenario where the principal is in a sedan, (the driver sitting at normal eye height) and the follow car is an SUV with the driver sitting at an elevated eye height. If both drivers perceive that they are moving at the same speed – for example, they both feel they are driving at 40 MPH – due to the eye height of the driver in the follow car he/she will be driving faster than the driver in the principal car. According to the study, the follow car’s speed can be off by as much as 15%. So if the driver in the follow car thinks they are driving 40 MPH, they are more than likely driving 46 MPH. If the driver in the follow car thinks they are driving at 60 MPH, they are probably going 69 MPH. And the higher you sit in the vehicle, the higher the speed differential.

To carry this one step further, an increase in speed of 15% would represent an increase of 30% in the energy the driver will need to manage in an emergency manoeuvre and an increase in 30% in the distance required to stop in the event of an emergency.

All this leads to the fact that driving the follow car is not easy; following distance will vary and require the driver’s constant attention.

Some thoughts on the two vehicle scenario:

1. The driver of the follow vehicle needs to be cautious of their speed. Lots of consideration needs to be given to who is driving the vehicle; putting a driver with little or no experience driving an SUV in a motorcade is problematic.
2. Preliminary data from the 2017 Executive/Security Vehicle Survey also indicates that when traveling the most often rented vehicle is an SUV, driven by a subcontracted security driver. We suggest that the driver has experience driving SUV’s, and is aware of the misconception of speed that an SUV creates.
3. There is a substantial difference between the handling capability of the lead vehicle (if a sedan), and the handling capability of the follow vehicle (if an SUV). The difference in handling capability, when coupled with the misconception of speed created by the follow driver’s eye height, can create a significant risk. The driver of the lead vehicle must be aware of their cornering speed. They need to understand that the follow car may not be able to corner at the same speed as the lead vehicle. They need to coordinate their movements. This can be accomplished by advancing the route.
4. Be cautious of the difference in stopping distance between a sedan and an SUV. Scenario: the lead vehicle is a Mercedes S 550 which can stop from 60 MPH in 128 feet. The follow-vehicle is a Suburban LTZ which can stop from 60 MPH in 138 feet. The Mercedes comes to a quick stop. At the elevated eye height, the Suburban driver could be moving at 69 MPH and take 30% more distance to stop the vehicle, so not accounting for reaction time the Suburban would need about 179 feet to stop the vehicle. If the driver of the follow vehicle is reacting to the brake lights of the lead vehicle, and considering an average reaction time of .75 Seconds, there would be an additional 76 feet added to the stopping distance, which would make the total stopping distance 255 feet – which would present a problem.
   

 

The Science of Walking or Driving  the Principal –  Time and Distance

An attack on the principal is a time, distance relationship. Moving the principal, driving or walking is managing time and distance. If there is an attack on the principal (AOP), driving or walking, any delay in the decision-making process will equate to less time and distance. No matter what level of skill the practitioners possesses if there is not enough time and distance to use the skill, bad things will happen.

An understanding of the basic principles of managing time and distance can be lifesaving knowledge.

Driving the Principal
While driving, our frame of reference for measuring  time and distance is attached to a speedometer, which supplies information in units of miles and hours – MPH. Whether you are driving (or walking) you do not have an hour or a mile to make decisions; in a vehicle emergency (accident or ambush), Miles Per Hour is an irrelevant unit of measurement.

As mentioned above, any delay in the decision-making process adds exponentially to the level of difficulty needed to survive the AOP. In a vehicle, delays are not measured in seconds, but in tenths of seconds. As an example; at 40 mph (58.8 Feet Per Second), in .2 seconds, the driver travels 11.76 feet, at 60 MPH (88.2 Feet Per Second) in .2 seconds the driver would travel 17.6 feet.

Why two-tenths of a second? Because that is how much time it takes to blink your eyes.
When you are driving 60 mph, literally in a blink of an eye, you are 17.6 feet closer to the problem, in a half a second you would be 44 feet closer and in a second 88 feet closer to the problem.

Any training that can speed up the decision-making process – by as little as a blink of an eye dramatically increase the chances of surviving the emergency.

Walking with the principal
Also, this concept of time and distance applies to all types of movements, including walking with the principal or standing in close proximity to the principal.

Consider that the “average” leisure walking speed is 3.1 MPH, and walking at a faster pace would bring the speed up to 5.6 MPH. Using these walking speeds, walking at 3.1 MPH is equivalent to walking 4.6 Feet Per Second, and walking at 5.6 MPH is equivalent to walking 8.2 Feet Per Second.

Unlike moving the principal in a vehicle where the speeds are high and decision time is measured in tenths of seconds, when walking with the principal the speed is low and time is measured in seconds, as an example, using the 3.1 MPH walking speed, a delay in perception of the problem of one second would mean the threat is 4.6 feet closer to the principal. In two seconds (count to two slowly), given the 3.1-mile example, if there is a delay in perception, the threat is approximately 9 feet closer to the principal.

Whatever the attack scenario, moving in a vehicle or walking, there is a time and a distance that will mitigate the problem.

Consider the concept of time and distance in the context of training. While training if the provider allows 5 seconds to solve a problem that needs to be mitigated in 2 seconds they create a false sense of security that can be exploited by those who wish to do you and your principal harm.

 

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The Science Behind Protection On The Move
By: Tony Scotti

Tony Scotti – International Security Driver Association (ISDA) –  ISDA is your essential resource for continuing education, benchmark research, and online learning programs, all designed to improve your skill set and advance your business.

For more information go to: https://isdacenter.org or http://securitydriver.com or email tonyscotti@isdacenter.org