Reference: Fataawa Noor ‘alad-Darb – Question No.5813, Page 250-251, Volume 11
Question: I am asking about a woman who works, and she has a driver as well as female staff who she drops off at various schools. She then returns home [alone] with her driver – [and all of this takes place] within the city. [So the question is] is this haraam or permissible?
Response: So if the women are with her [for the entire journey – there and back], then it is not haraam – so long as the driver is trustworthy. If, however, she is alone with him, then that is haraam, because the Prophet (sal-Allaahu ‘alayhi wa sallam) forbade a man and a woman from being alone together. And there is no difference whether the [travelling] distance is short or long within the city; as for [her] travelling without a mahram, then that is haraam – even if she was accompanied with other women.