What indicates that road conditions have changed when driving?

Feeling vibration in your steering wheel can indicate that road conditions have changed, particularly if the surface you're driving on has become uneven or if you're encountering gravel, potholes, or other irregularities. These vibrations can signal that the car's tires are reacting to a different type of road surface, alerting you to adjust your driving behavior as necessary for safety.

While hearing a loud noise might indicate something wrong with the vehicle or external factors, it does not specifically point to a change in road conditions. Seeing road signs provides information about upcoming conditions or rules of the road, but does not directly indicate a change in the current surface you're traveling on. A sudden gust of wind may affect vehicle control, particularly in larger vehicles, but it does not relate to the road surface itself. Thus, the sensation of vibration in the steering wheel directly reflects changes in the road itself, making it the most relevant indicator among the options.