The volume of passenger transport has been increasing in Slovenia for several decades, primarily due to the growth of the most unsustainable modes – passenger cars and (especially after 2002) air transport. This growth stopped after the economic recession in 2008. The volume of public transport has been declining for decades, especially the modal share of bus services. In the last decade, the modal share of public transport stabilised, but at a much lower level compared to 1991, when Slovenia became independent.

Data on air pollution shows that Slovenian cities are overpolluted, primarily with NO₂ and PM₁₀. Transport is one of the main causes of this pollution. In general, air quality is improving, especially since the economic downturn in 2008 after which the volume of passenger traffic was reduced.

In 2012, greenhouse gas emissions from transport in Slovenia had increased by 185% compared to 1986. Also, at the EU level, GHG emissions from transport by far exceeded the growth – in the period 1990–2014, they increased by 13% (in Slovenia, they increased by slightly less than 97% in the same period). A major source of GHGs is road transport, which contributed approximately 99.2% in 2012. The share of GHG emissions from transport (31% in 2012) and insufficiently effective measures to reduce GHGs makes fulfilling commitments under the Kyoto Protocol difficult to accomplish in Slovenia.