Electronic Stability Control (ESC) is the computer-controlled braking of individual wheels to assist a driver with maintaining control of the car in critical driving situations.
It has been around since the mid-’80s, and in the United States, it became mandatory for all new cars in September 2011.
The Benefit of ESC
The value of ESC is that it interprets the information before the average driver (the crucial word is “average”) or even the above-average driver can sense the problem. Once the ESC computer analyzes the driver’s inputs to the vehicle, it starts to set the car on the correct path before the “average driver” can figure out what’s happening.
Electronic Stability Control accomplishes this by measuring throttle position, steering wheel angle, and G forces pushing on the vehicle’s center of gravity. The computer compares the vehicle’s intended path to the path the car is actually taking. If it’s not doing what the driver wants it to do or what is not in the best interest of the passengers’ safety, the ESC computer takes over. ESC will not allow the driver to push the vehicle to its maximum capability.
When ESC decides to handle the driving chores, it applies one of the front brakes, or in some systems, one of the front and/or rear brakes, to straighten the car and put it back on the path you wanted to go.
The Impact of ESC
The issues for Security Drivers are the words average, problem, and the definition of safety. For an “average” driving population, the “problem “is created because their input into the vehicle (steering – gas pedal – braking) was contrary to the safe operation of the vehicle.
In a security “problem,” the security driver is purposely driving the vehicle in a manner that will push the vehicle’s ESC algorithm limit.
When Does ESC Take Control?
So, the question becomes when does the ESC intrude and take over control of the vehicle and prevent the Security Driver from using the maximum capability of the vehicle?
For decades we have been preaching and teaching that a good Security Driver can use a minimum of 80% of the vehicle’s capability. (A supporting article is located in the Index below.)
Chevy Suburban Example
Let’s look at a popular Executive Vehicle, the Suburban, and take a quick look at the definition of vehicle capability.
The vehicle’s capability is defined as how many G’s it can absorb before it starts to lose control. For the 2023 Suburban, Car and Driver magazine measured that number to be .75 G’s, which means the Suburban can absorb 75% of its weight, pushing on the vehicle’s center of gravity before it starts to lose control. (For more information about vehicle capability, look at the YouTube Video located in the Index below)
Car and Driver magazine arrived at the .75 G’s by driving the vehicle around a skid pad; arguably, it is not the best method of measuring handling and the driver’s ability to use the vehicle’s capability.
The best test for that measurement is labeled ISO 3888 – 2. If you have been through an old Scotti School or Vehicle Dynamics Institute (VDI), the Lane Change is the ISO test.
A test conducted by Car and Driver magazine measured that the ESC reduces the handling capability of the Suburban by 27%. So the ESC takes over control of the Suburban at .55 G’s. Working out the math, it is unsurprising that .55 G’s is 70% of the Suburban’s capability, so it makes sense that the ESC will take over when the “average driver” approaches 70% usage of the vehicle.
Can a trained driver get more from the vehicle?
Yes. Using 80% of the Suburban capability would apply .6 Gs to the vehicle’s center of gravity. If you attended a Scotti School in the past or a VDI program in the present, you would be required to apply .6 G’s to the Suburban without losing control.
If you drove the Suburban through the Lane Change, with the signal at the entrance gate’s beginning, the 80% minimum speed would be 30 MPH or 48.3 KPH; most drivers would reach 34 MPH or 55 KPH.
The Suburban’s ESC would take control of the vehicle at 25 MPH or 40KPH; it could also change the vehicle’s path and not allow the driver to drive into the exit gate.
Also of interest is when we (ISDA and VDI) analyzed the Omar García Harfuch ambush, we found that if the driver had turned the steering wheel to avoid the incident and jumped a curb, the ESC of the Suburban would not have allowed him to do so.
It should go without saying that vehicles used in security driver training need to be equipped with ESC. In the classroom and in hands-on training, students need to be exposed to the effects of ESC on Secure Transportation.
ESC can create problems for the Security Driver. Keep in mind that above-average drivers anticipate problems others just react to the problem.
The Driver Equation = Driver Survivability
The Science of Security Driving and the 80% Standard
Technology is Changing Executive Vehicles – ADAS