Do I have to use components that have a Component Type Approval (CTA)?
No. However, if you use a road vehicle component that do not have a CTA, it is your obligation to demonstrate the ADR compliance of the component to support your Vehicle Type Approval application. You will also become responsible for the compliance of the component. Using a component with a CTA will streamline the process, as you can simply hold on file the CTA number for the component rather than having to retain all the supporting evidence.