Episode 168 – The Science of Backing Up

Backing up slowly can be a problem but backing up fast is hard and dangerous if not done correctly. With that said, it is by far one of the most valuable driving skills to have, and a Security Driver can acquire. Along with being hard to do, it is hard to teach and, if not taught correctly – dangerous. What makes it hard and hazardous is the definition of fast. How fast you can drive in reverse is limited to the vehicle’s gearing; in most vehicles, you can drive as fast in reverse, or a little quicker, as you can in 1st gear. The maximum speed depends on the type of vehicle. Very few get above 25 MPH – 40KPH, and those reverse speeds are an exciting experience.

Caster Angle

What creates excitement is that cars are designed to go forward. Automobile suspensions possess a quality known as “caster”. Caster is the force that helps to straighten out the front wheels after turning a corner. Caster also gives the car stability while traveling forward. Unfortunately, this stabilizing forward force destabilizes the car while it’s in reverse. Also, the difficulty is that while driving in reverse, the steering wheel will not center automatically. If you loosen your grip, it will stay in its last position. This is a characteristic of “vehicles in reverse,” which creates an unstable vehicle.

The issue is that since the car becomes unstable while traveling backward, small changes in steering wheel movement cause significant changes in the way the car reacts to your inputs. Of course, the faster you go in reverse, the more complicated control becomes. There is nothing you can do about caster. You need to understand that it’s there, live with it and learn to control it.

Adding to the excitement of driving in reverse is that the correct direction to move the wheel can be confusing. The problem is mainly perceptual. The proper way to move the wheel is quite simple: Move the top of the steering wheel in the direction you wish the car to move. It’s no different from what you do while driving forward; it just feels different in reverse.

Suggestion for Reversing Out of the Kill Zone

If the scenario requires that you reverse out of the kill zone, the more distance you can put between you and the problem in front of you, the better. The quicker you get yourself going backward, the better off you are. For example, if we use 30 MPH or 48 KPH as an average back up speed (a fast speed in reverse), every second is 45 feet or 13.7 Meters of distance you put between you and the problem. In three seconds, you will be 135 Feet 45 Meters away from the problem. If you sit there for 1.5 seconds and contemplate your navel, you have given up around 68 Feet – 20 Meters of distance. At 30 mph or 48 kilometers per hour, the driver surrenders 45 feet or 13.7 meters in space for every second they remain motionless.

Back up as fast as you can and as straight as you can for as far as you can since backing up straight is much easier than backing up while turning. There will be scenarios where you may have to back around objects, which will be addressed later.

Even if there is an opportunity to turn, in a short distance, don’t, since you want to put as much distance as possible between you and the problem before you turn the vehicle. If you are in range of any weapons, you do not want to expose the vehicle’s side to the enemy.

A vehicle’s handling characteristic in reverse varies a great deal from vehicle to vehicle. If you have to back up around obstacles never combine a great deal of steering wheel movement with a heavy foot on the gas pedal. The faster you travel in reverse, the more sensitive the steering becomes, and the greater the chance for disaster. If you have to drive around an obstacle in reverse, decrease your speed before turning the wheel. The correct amount of steering and speed in reverse can only be determined through practice. Because of the caster mentioned earlier and the instability it creates, it doesn’t take much to flip a vehicle moving in reverse.

As mentioned earlier, the handling characteristics of a vehicle in reverse is not the same as driving forward. Because a vehicle handles well going forward is no indication of how it will handle driving in reverse. For example, if a vehicle moving forward can drive around an obstacle at 60 MPH – 96 KPH, the same vehicle going around the same object will lose control while driving in reverse at 20 MPH – 32 KPH.

Some vehicles have a device called “the governor,” limiting the speed while driving in reverse. The time to find out that you have a governor on the vehicle preventing you from driving fast in reverse is before you’re facing a kill zone. As a test, put the vehicle in reverse and accelerate; if there is a governor on the vehicle, the engine will misfire at around 10 MPH – 16 KPH.

Vehicles that are heavily loaded to the rear have a higher chance of losing control; however, since in most scenarios, there isn’t much that can be done about having a vehicle loaded in that manner, the driver needs to be aware of what can happen.

It was mentioned earlier that while driving in reverse, if you loosen your grip on the wheel, it stays in its last position so you’ll need to regrip to move the steering wheel and some cases you may have lost the top of the steering wheel. Add a visually hint – With the front wheels pointed straight, put a piece of tape on the top of the steering wheel. If you start to lose control, it will tell you where straight ahead is. If you look at an in-car camera shot of a NASCAR car, you will see tape on the top of the steering wheel.

A Case Study of the Science of Backing Up

Our forensic analysis of the Omar Garcia Harfuch (OGH for short) ambush indicated that the driver attempted to back out of the Kill Zone. A video and photos showed that the vehicle initially stopped 20 Feet/ 6 Meters in front of the attacker’s truck. Other images and videos show that the Suburban’s final resting place was 66 Feet/ 20 Meters back from the truck, which indicates that the driver drove in reverse 46 Feet /14 Meters away from the kill zone before the vehicle stopped at its last resting place. It also suggests that, at that time, the driver was still capable of putting the car in reverse and backing up.

Further analysis indicated that the Suburban remained stationary at the 20 Foot/ 6 Meters mark for 2 to 2 1/2 seconds before attempting to reverse. 

The ISDA and the Vehicle Dynamics Institute test team recreated this scenario matching the dimensions developed in our analysis. In the process of conducting the tests; they discovered a vehicle characteristic that explains our hypothesis of why the driver seemed to have sat in the kill zone 20 Feet/ 6 Meters from the attacking truck for approximately 2 seconds before moving the vehicle or trying to move the vehicle.

The VDI team suggests from there testing that the vehicle’s ADAS ***Transmission Control Module (TCM) system caused the two-second delay.

The TCM systems can create a severe issue with backing out of the kill zone; hence the VDI team spent a significant amount of time ensuring that they recreated the scenario accurately, tested under various environmental conditions, and drivers of varying levels experience.

Lessons Learned and Recommendations

Training providers need to determine if the student’s operating a vehicle with the Transmission Control Module. If they do, they need to discuss the effects of TCM on reversing.

Those who train students working in a high-risk environment need to examine the reversing characteristics of the operational vehicles the student will be driving and the environment that they will be driving in.

Security drivers need to know the characteristics of the vehicle while driving in reverse.

Keep in mind that all new vehicles have speed limiters, preventing the vehicle from reversing quickly. 

Training to reverse the vehicle out of a dangerous scenario cannot start with the vehicle stopped. The training exercise has to start with the student driving into the backing exercise at a predetermined speed.

Test your vehicle reversing characteristics. The time to know that there is a limiter on the vehicle or ADAS system is not when you are facing a problem.

Backing out of the kill zone is one of the necessary skills required for a security driver. It is mandatory that the driver find a safe place they can drive their operational vehicle. Drive the vehicle at a speed that fits the environment. Stop the vehicle quickly, put the vehicle into reverse and experience the vehicle’s reversing characteristics.

This is another example of why protective driver training instructors must grasp the concept of ADAS in the vehicle algorithms.

There very well could be a time when the vehicle’s algorithm is deciding to maximize safety. It may be putting the security of the principal and the driver in harm’s way. That is the difference between a security driver and a chauffeur. 

Training needs to train students to work with the vehicle’s algorithm to maximize the vehicle’s performance.

**40 MPH/64.4 KPH is the speed determine from data point two to be the Suburban’s speed entering the kill zone.

*** A transmission control module is an electronic mechanism that collects data and processes signals within your transmission in order to regulate the transmission’s gear shifting.

If you have interest in going much deeper into these types of topics, I invite you to check out the International Security Driver Association’s website ISDACenter.Org and get access to the encyclopedia of executive protection and secure transportation – The ISDA knowledge center. The knowledge shared encompasses a wide range of EP and ST focused topics with resources, information, and metrics.

 For more information on all of the member benefits, head over to https://isdacenter.org.

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