Matrix API : Change default speeds for driving-car

Hello Everyone,

We are using the latest docker image to host a local instance of ORS and would like to know how we can modify the speed limits that the Matrix API uses to calculate distance and duration between two or more points?

I understand that the speed limits are set by profile and that there is a car.json file, but is there a way to edit this file or use a custom json file without cloning the repo?