Why must air tanks be drained regularly?

Draining air tanks regularly is crucial to removing water and oil that can accumulate in the air brake system. Over time, condensation forms in the air tanks, particularly in humid or wet conditions. If this moisture is not eliminated, it can freeze in cold temperatures, leading to blockages and ultimately causing brake failure. Ice can obstruct the proper functioning of the air brake components, making it unsafe to drive. This necessity for regular drainage ensures that the air braking system remains fully operational and reliable, thereby maintaining safety on the road.

While the other options may relate to aspects of vehicle maintenance and performance, they do not address the specific issue of moisture management in the air tanks that can lead to brake failure.