Virginia CDL General Knowledge Practice Test

The correct answer identifies the two primary types of air brake systems used in commercial vehicles: single and dual air brake systems.

Single air brake systems consist of one air reservoir that supplies air to the brake components. This design is less complex but can pose a safety risk; if a failure occurs in the single system, the braking ability can be compromised entirely.

Dual air brake systems, on the other hand, feature two separate air systems. This redundancy enhances safety, as one system can usually compensate for the failure of the other, providing more reliable braking performance. Dual systems are now standard in most modern trucks and buses due to their increased safety and reliability.

Other options such as hybrid and pneumatic, disc and drum, or automated and manual refer to different aspects of braking technology or system configurations, but they don’t represent the foundational categories of air brake systems like single and dual do. Understanding this distinction is crucial for CDL drivers, as it informs vehicle maintenance, safety checks, and operational protocols related to brakes.