Being in the driver's seat is often used to refer to being in control of a situation. However, there are several other synonyms that can be used interchangeably with this phrase. One such synonym is 'in charge', which also implies a person's authority and responsibility in a particular situation. 'At the helm' is another synonym. This phrase is often used to refer to leadership roles. Another common synonym is 'in control', which suggests that a person has complete control over the situation. 'At the forefront' is another phrase that can be used to express being in charge of something. Other synonyms include 'leading the charge', 'at the center of things', and 'calling the shots'.