Road emissions by type of road

Motorway emissions were 2 MtCO₂e in 2018, an increase of 4.2% from the previous year, accounting for 20.2% of road emissions. Motorway emissions have increased substantially since 1990, with the 2018 figure 81% above that of the 1990 baseline. This increase in motorway emissions since 1990 has coincided with a substantial increase in the length of Scotland’s motorway network. Between 1990 and 2017 Scotland’s motorway network increased in length from 312km to 645km. Motorway vehicle kilometres rose from 3242 million in 1990 to 8518 million in 2018.^[4]

Rural road emissions were 4.4 MtCO₂e in 2018, accounting for 43.5% of road emissions, and urban road emissions were 3.6 MtCO₂e, accounting for 35.5% of road emissions. The methodology used to classify urban and rural roads has changed since the last publication, therefore it is not possible to compare the most recent emissions figures for these roads to previous years.

In 2018, rural and urban driving emissions decreased by 3.4% and 3%, respectively, reflecting drops of 0.2 MtCO₂e for rural roads and 0.1 MtCO₂e for urban roads. On the other hand, motorway driving saw an increase of 0.1 MtCO₂e or 4.2%. No further expansion of the road network was recorded for 2018. Since baseline, motorway driving has been on the increase, with motorway-generated emissions rising by 81% since 1990 equating to 0.9 MtCO₂e. Whilst motorway-related emissions have experienced an increase since the baseline period, rural driving has dropped 5.6% or 0.3 MtCO₂e. Urban driving since the baseline has increased 0.2 MtCO₂e, or 5.1% and decreased 0.1 MtCO₂e or 2.9% in 2018.