What must you have in order to steer or brake a vehicle effectively?

To steer or brake a vehicle effectively, traction is essential. Traction refers to the grip between the vehicle's tires and the road surface, which allows for efficient steering control and effective braking. Without adequate traction, the tires may slip or skid, making it difficult to maneuver the vehicle safely or to stop when necessary. This grip is influenced by various factors, including road conditions (such as wet or icy surfaces), tire condition, and vehicle weight distribution.

While power steering and power brakes can enhance vehicle handling and reduce the effort needed to turn the steering wheel or apply the brakes, they do not replace the necessity for traction. Sufficient space is also significant for safe driving, especially when braking, but it is not directly related to the vehicle's ability to steer or brake effectively. Therefore, traction is the key factor that directly impacts a driver's capacity to control the vehicle in both steering and braking scenarios.