What is the purpose of the air brake system in passenger vehicles?

The air brake system in passenger vehicles is primarily designed to provide reliable stopping power. This system is crucial for the safety of passengers and the effective operation of the vehicle. Air brakes use compressed air to activate the brake mechanism, allowing for strong and consistent braking performance. This is especially important in larger vehicles or those carrying passengers, where effective stopping is vital for avoiding accidents.

The other options, while they may have relevance in different contexts, do not accurately capture the primary function of the air brake system. Enhancing fuel efficiency pertains more to engine design and vehicle aerodynamics rather than braking systems. Cabin comfort is not related to the braking mechanism but to the design and features within the passenger area. Reducing vehicle weight often involves materials and structural considerations, which again do not pertain directly to the operation of the air brake system. Overall, the focus of air brakes is solely on maximizing the stopping capabilities necessary for safe passenger transport.