The driver has applied more energy to the vehicles center of gravity than the vehicle can accept. These situations are preventable and occur when the driver is going too fast for the road conditions, or when a tire exceeds the available grip due to an environmental factor. This loss of control can occur while responding to an emergency or just routine driving. The objective is to regain control and each vehicle manufacture reaches that goal in a different way.
ESC will use all or a combination of anti lock brake components, traction control systems, steering wheel rotation and yaw sensors (sensors that determine when a vehicle spins around its own axis) and will automatically activate when the car starts to spin or slide.
Some ESC systems react to the data it reads from the steering wheel, (if this is the case your steering inputs are critical and you must have the steering wheel pointed in the direction you want the vehicle to go) while others react just off the readings from the yaw sensor. Know your vehicle by checking with the vehicle manual, the manufacture or qualified mechanic to determine what type of stability control system your cruiser is utilizing.
ESC will assist drivers in controlling the direction of the vehicle during an evasive or cornering maneuver where a tires traction nears or exceeds its limits.
When a tire nears its limit of grip the car will begin to show signs of a slide. This is when the sensors will send a signal to the brakes and engine. The brakes will be applied to the wheel or wheels that will guide the vehicle back into its intended path.
If the vehicle is not equipped with ESC, during cornering or evasive maneuvers the car will understeer, oversteer or go into a 4-wheel slide. Even a highly trained driver will have difficulty regaining control without the help of ESC. REMEMBER: most drivers are not highly trained, including the law enforcement community!!
For all the EVOC Instructors, know that most of your department vehicles are equipped with ESC, this is the time to get out your measuring tapes and calculators, apply some laws of physics and create a radius turn and/or an evasive exercise that will activate the ESC feature.
The exercise should demonstrate to the officer what happens when ESC activates, and the dangers that occur when they exceed the vehicles capabilities. You will have to figure out the radius of the turn, speeds for activation and speeds for loss of control. Remember to emphasize complete vehicle control at all times and always stay within the vehicles limits.
When we overdrive our vehicles, even with all the safety enhancements in today’s cars, sooner not later bad things will happen. Your job is dangerous enough, do not make it anymore dangerous then it has to be.