Yellow surface hinges have been replaced by HingeConstraints for a few years now. We have a very simple tutorial with a script included to create a car using constraints. There’s also tons of cars and chassis on the toolbox that can be taken and customized.
That being said, this change is not removing the ability to use yellow surface hinges, as stated in the post. You will still be able to use them to build cars with VehicleSeats after this change.