Is the speech of a driver about another driver whom he sees considered backbiting about an unknown person, or backbiting about a known person? And if a person speaks about an official who is unknown to me, is that considered backbiting about an unknown person, and is there no sin in it? And if one should avoid any of these situations, is it unlawful (haram) or merely disliked (makruh)?

Prohibited backbiting is mentioning a specific person with something they dislike if they were to hear it. The person is identified by anything that makes their identity understood. So, if the driver is identifiable, then backbiting about him is forbidden, unless there is a legitimate interest that permits backbiting, such as seeking advice or help in changing a wrong. If the person responsible is unknown and not identifiable, then it is not considered prohibited backbiting. However, if the person is identifiable, then backbiting about them is forbidden, even if you do not know them completely.

Prohibited backbiting is not permissible to listen to, and it must be denounced verbally if no harm is feared. Otherwise, it should be denounced in the heart while leaving the gathering. Bad speech is not a characteristic of a Muslim.