Which brake system is preferred when dealing with heavy vehicles?

Air brakes are preferred for heavy vehicles primarily because they provide significant force and reliability necessary for safely stopping large and heavy loads. Unlike hydraulic brakes, which can succumb to loss of brake fluid pressure or overheating, air brakes utilize compressed air to engage the braking mechanism, allowing for greater power without risking fluid leaks.

Heavy vehicles typically require more braking power due to their mass and the demand for consistent performance under various conditions. Air brakes have the advantage of being able to maintain effectiveness, even in demanding circumstances, such as descending steep grades. They can also be equipped with automatic slack adjusters and fail-safe features, ensuring that if air pressure falls below a safe level, the brakes will engage automatically.

In contrast, while disc brakes are effective and often used in lighter vehicles for their quick response and heat dissipation, they may not provide the same level of stopping force required for larger vehicles. Hydraulic and mechanical brakes can also be less effective under the high stresses and demands faced by heavy vehicles, which makes them less desirable for this purpose. Thus, air brakes emerge as the optimal choice for ensuring both performance and safety in heavy vehicle braking systems.