[put] the brakes on

to prevent something from happening or making more progress

The idiom "put the brakes on something" originates from the literal action of applying brakes to slow down or stop a vehicle. It has been figuratively extended to describe the act of slowing down, reducing the pace, or stopping the progress of a particular activity, plan, or situation. The idiom emphasizes taking deliberate steps to control or limit the momentum of something, often in response to concerns about its speed or potential consequences.

Faced with rising costs, the company had to put the brakes on their ambitious expansion plans.
Concerns about environmental impact led the government to put the brakes on the construction of the new highway.
We need to put on the brakes and reconsider our plans before moving forward.
The company's leadership decided to put a break on their aggressive marketing campaign to evaluate its effectiveness.
The manager decided to put on the brakes when he realized the project was going off track.

to slow down or stop a vehicle by using the stopping mechanism

He put the brakes on when he saw the red light ahead.
She put a brake on the car when the light turned red.
The driver put on the brakes hard as the light turned yellow.
The driver had to put the brakes on quickly to avoid hitting the car in front.
I had to put a brake on my scooter when I saw the pothole ahead.