emergency brake

noun

Also called parking brake. a special brake used to prevent a motor vehicle from rolling after it has stopped or been parked.Compare brake¹(def 1).
any brake meant to stop a vehicle in an emergency.

Origin of emergency brake

First recorded in 1895–1900

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

In a flash he was up, cutting off the power and bearing down on the emergency-brake.
Motor Matt's Clue
Stanley R. Matthews
He saw the danger, and with his hand upon the emergency-brake he threw his weight upon the wheel.
The Spell
William Dana Orcutt