With existing measures' (WEM) scenario: By 2020, 2030 and 2035, Switzerland's total greenhouse gas emissions under the WEM scenario are projected to decrease to 85.4 per cent, 77.4 per cent and 74.9 per cent of the emissions in 1990, respectively. While the source category covering residential and commercial/institutional buildings (1A4) dominated total emissions in 1990, its emissions gradually decreased and are projected to continue on a decreasing pathway, reaching a reduction of 31.9 per cent by 2020 compared to 1990 (Fig. 19). Emissions from transport (1A3), on the other hand, increased considerably (by 13.7 per cent) between 1990 and 2008, exceeding emissions from residential and commercial/institutional buildings by 2007. Emissions from the transport sector are largely driven by passenger cars. Only recently, efforts to reduce specific vehicle emissions seem to become effective. Accordingly, thanks to the CO emission regulations for newly registered vehicles stipulated in the second CO Act (section 3.4.2), as well as thanks to the autonomous technological progress, greenhouse gas emissions from the transport sector are projected to decrease over the coming years. The emission reduction projected to be achieved by 2020 is 10.9 per cent compared to the highest level in 2008, meaning that emissions from the transport sector are still 1.3 per cent above the emissions in 1990. Emission reductions from the source categories covering residential and commercial/institutional buildings (1A4) as well as transport (1A3) dominate the projected evolution of total greenhouse gas emissions under the WEM scenario. Emissions from other source categories remain about stable and/or are of minor importance, with the exception of the Fgases, where projections suggest the peaking of emissions before 2020 and a decline thereafter (Fig. 17);