Pennsylvania CDL Practice Exam

Downshifting an automatic transmission is particularly recommended when going downhill. The reason for this is that downshifting allows the engine to take on some of the workload of slowing the vehicle, which can help maintain a safe speed. This practice is often referred to as "engine braking." When you downshift, the higher RPMs generated by the engine can provide additional resistance against the weight of the vehicle rolling downhill, making it easier to control the speed without relying solely on the brakes.

Utilizing engine braking improves brake performance and longevity, as it reduces the wear and tear on braking components. It is crucial in downhill scenarios, especially when managing heavier loads, as it enhances overall vehicle stability and control on grades.

In contrast, downshifting may not be beneficial in the contexts of flat roads, when stopping at a light, or while making turns, as the primary purpose of downshifting is to manage speed and maintain control on descents.