There is a loud roaring noise while driving. The noise gets louder when vehicle speed increases. Which of the following could be the cause?

A loud roaring noise that increases in volume with vehicle speed is typically indicative of a worn wheel bearing. As the vehicle accelerates, the load on the wheel bearings changes, and any wear or damage leads to increased friction and noise. Worn wheel bearings can cause a distinctive roaring sound due to the uneven surfaces struggling against each other as the wheel turns faster.

In contrast, while a worn power steering pump, ball joint, or power steering gear can produce various noises, they are generally not linked to an increase in noise that correlates directly with vehicle speed in the same way that wheel bearings do. For example, a power steering pump might produce whining or groaning noises, especially when turning or under load, but these sounds do not typically escalate with speed. A worn ball joint may create clunking or rattling noises, particularly over bumps, rather than a consistent roaring sound, and similarly, a worn power steering gear is more associated with hissing or grinding noises rather than the roaring linked to wheel speed.

Thus, the rapid increase in noise level with speed strongly points to the condition of the wheel bearings as the likely culprit.