What is a significant risk when driving a large vehicle with malfunctioning air brakes?

The risk of losing control and causing an accident when driving a large vehicle with malfunctioning air brakes is significant because braking systems are crucial for safely operating large vehicles. Air brakes are designed to provide a strong and reliable means of stopping. If the air brake system is not functioning properly, it can lead to longer stopping distances or complete brake failure, making it extremely difficult to control the vehicle in emergency situations. This inability to stop effectively can result in serious safety hazards not only for the driver but also for other road users.

Other factors like fuel efficiency, tire wear, and emissions levels can be impacted by various vehicle conditions, but they do not directly relate to the immediate safety of handling and controlling a large vehicle like malfunctioning brakes do. The primary concern with air brake failure is the direct risk it poses to the driver's ability to manage the vehicle adequately, which can lead to potentially catastrophic accidents.