After the UK left the EU, Brussels introduced the General Safety Regulation 2, which set out principles to make cars safer with the fitting of key components.
These included a pre-installed interface to allow a breathalyser locking system to be installed, as well as Event Data Recorders, which are similar to black boxes found in aircraft.
As I said those people can already have an interlock device installed in their car without any special “interface” mandated into every car by the government. This is just the “it’s for the children” propaganda repackaged into something else.