What is the primary function of a sway bar in a vehicle?

The primary function of a sway bar, also known as an anti-roll bar or stabilizer bar, is to reduce body roll during cornering. When a vehicle turns, the weight of the car shifts to the outside of the turn, which can cause the body to lean or roll. This body roll can lead to decreased traction and stability, negatively affecting handling and driver confidence. The sway bar connects the left and right sides of the suspension. When one side of the vehicle experiences compression due to cornering, the sway bar twists and applies force on the opposite side, which helps to counteract that roll. By doing so, it keeps the vehicle more level, maintaining better tire contact with the road and improving overall handling dynamics.

The other options, while related to vehicle performance, do not accurately describe the sway bar's function. The sway bar is not designed to increase engine power, improve fuel efficiency, or enhance braking performance. Each of those functions is managed by different components and systems within the vehicle.