What action does the ATC take when a drive wheel starts to spin?

When a drive wheel starts to spin, the appropriate action is to apply air pressure to brake the wheel. This response is crucial for maintaining control of the vehicle and preventing further wheel spin. By applying air pressure to the brake, the system can help regain traction by reducing the speed of the spinning wheel.

This mechanism is particularly important in situations where the drive wheel encounters slippery surfaces, such as ice or mud. Without intervention, a spinning wheel can lose contact with the road, leading to a loss of control or an increase in stopping distance. The application of brakes to the spinning wheel helps stabilize the vehicle and ensures that power is directed more efficiently to wheels that have sufficient traction.

The other options do not offer a reliable solution in the context of managing a spinning drive wheel. For instance, applying engine power would exacerbate the spinning condition, risking further loss of control. Reducing engine power may not provide immediate assistance in regaining traction, while activating traction control on all wheels may not be applicable in every situation, especially if the system is not designed to respond to a singular spinning wheel effectively. Therefore, applying air pressure to brake the spinning wheel is the most direct and effective action to counteract wheel spin.