Best way to stop a car after a finish line?

I’m making a simple racing game using the Car Controller from the Standard Assets pack (Standard Assets 2018.4 | Check out Starter Assets: First Person & Third Person | Asset Packs | Unity Asset Store).
What would be the best way to apply brakes and stop the car gradually after it reaches a finish line?
I know how to simply destroy the car object or stop the related scripts but that’s not quite the result I want.

Can you elaborate? I’m sorry I’m still new at this. @tormentoarmagedoom