in the driver's seat
idiomUK /ɪn ðə ˈdraɪvəz siːt/
US /ɪn ðə ˈdraɪvərz siːt/
Being the person who is in charge and makes the decisions.
After the election, she was in the driver's seat and could change the rules.
OTHER MEANINGS
2. Literally sitting in the seat where the driver controls a car.
The child pretended to be in the driver's seat and turned the wheel.
3. Having the advantage or leading position in a competition or situation.
With two goals ahead, our team was in the driver's seat for the rest of the match.
4. Being responsible for guiding a project or plan forward.
As the new manager, he is in the driver's seat for the whole project.