The first car to use HFO-1234yf instead of HFC-134a for its air conditioning system is already being sold in Europe, according to reports in the auto press.

Other car makers could follow and a number of deals are said to have been signed.

EU Directive 40(2006) calls for a total ban in car air conditioning systems of HFCs having a GWP (global warming potential) higher than 150, for new vehicle types from 1 January 2011 and for all new vehicles from 1 January 2017.
A number of car manufacturers have been granted the right to continue using HFC-R134a in new models until HFO-1234yf is available in larger volumes.
Meanwhile, the US SAE (Society of Automobile Engineers) has released the 2012 update of its SAE J2727 Standard which includes HFO-1234yf, to replace the 2008 version.

The standard is intended to serve as a means of estimating the annual refrigerant emissions rate from new production systems equipped with specified component technologies. It provides emission values for various component technologies that are currently available. It can be expanded as new technologies are commercialized.

Source: RAC