Dynamic stability in the context of cars refers to technology that improves the safety of a vehicle on the road by detecting any loss of control and taking over from the driver. It works using a combination of many elements, including Automatic Braking System (ABS), Electronic Stability Control (ESC), Electronic Brake-force Distribution (EBD), and Dynamic Stability Control (DSC). All work to maintain control of the car on the road to prevent accident or injury.
Different manufacturers have different names for dynamic stability, but the technology is largely the same. A combination of software programs run on the car's computer to maintain grip and keep the car and its passengers safe on the road. There are a series of sensors on each wheel, the chassis, suspension, and in the engine that monitor the car's movements. The software measures the intended direction of travel by monitoring the steering angle and yaw of the car. If it detects the vehicle is traveling in a different direction than the steering, the program kicks in.
For example, if the software detects the car is going to lose grip on a corner, the dynamic stability control comes into play and several things can happen. First, the software applies the brakes gently to the wheels using the ABS. If the car has EBD, the program can apply the brakes on the wheels that still have grip. It can also reduce power to the wheels losing grip using ESC, especially in performance or four wheel drive cars. All this is done within tenths of a second, often long before the driver even knows anything is wrong.
Depending on the direction of the skid, or loss of grip, the dynamic stability control will brake or reduce power on the wheels to oppose the skid, allowing the driver to regain control. If the situation is severe enough, the program can also reduce power to the wheels, change gears, or apply brakes more forcefully. All this is designed to allow the driver to regain control or bring the vehicle to a stop as safely as possible.
Most new cars have some or all of these features, especially ABS. Most major manufacturers now include dynamic stability control in all of their cars. While there were fears that all these electronic safety measures would encourage drivers to perform beyond their ability, the effectiveness of it to avoid accidents is often seen to make that risk worthwhile.
Dynamic stability in a car is a combination of systems that work together or alone to help a driver regain control of a vehicle. Software programs monitor the direction and yaw of the vehicle and only intervene when it detects the loss of that control. The computer does not drive the car; it is a driving aid that is there to help when things get out of control.