What might indicate that you are driving on an icy road surface?

A sudden reduction in tyre/road noise can indicate that you are driving on an icy road surface. When vehicles drive on icy roads, the contact between the tyres and the ice can create less friction than on dry or wet surfaces. This can lead to a quieter ride because the usual road noise generated by the tyres is significantly reduced. The absence of the typical sounds associated with road noise may alert you to the presence of ice, prompting a driver to adjust their speed and driving style accordingly for safety.

In contrast, a decrease in vehicle speed can occur for various reasons, not solely due to icy conditions. Increased traction, on the other hand, would not be characteristic of icy surfaces; instead, icy roads typically result in a loss of traction. Lastly, while vibration in the steering wheel might occur for various reasons, such as an unbalanced wheel or road irregularities, it does not specifically indicate that the surface is icy.