3. Efficiency of transport modes
Carbon Account for Transport No. 11: 2019 Edition
3. Efficiency of transport modes
The emissions figures for each transport mode presented in the previous section are largely dependent on the usage of that transport mode, therefore they do not give any information on how efficient that mode of transport is for a passenger to travel on. This section presents a discussion of the efficiency of various transport modes, measured in terms of their emissions per passenger kilometre (pkm). The data presented in this section are provided by DEFRA[7] and are for the UK as a whole, not just Scotland.
The table below provides the average efficiencies of key transport modes for the years 2012-2017.
| Sector | Mode and fuel | gCO2e/pkm | |||||
|---|---|---|---|---|---|---|---|
| 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | ||
| Road | Average petrol car | 133 | 131 | 128 | 128 | 129 | 124 |
| Average diesel car | 124 | 121 | 123 | 122 | 123 | 119 | |
| Average hybrid car | 89 | 87 | 89 | 86 | 89 | 79 | |
| Average petrol motorbike | 119 | 119 | 120 | 120 | 120 | 117 | |
| Average bus | 112 | 112 | 110 | 109 | 102 | 103 | |
| Average coach | 29 | 29 | 29 | 29 | 29 | 28 | |
| Rail | National rail | 58 | 49 | 47 | 45 | 49 | 47 |
| Light rail and tram | 68 | 60 | 62 | 55 | 54 | 44 | |
| Ferry | Average foot and car passengers | 116 | 116 | 116 | 116 | 116 | 116 |
| Aviation | Average domestic flight | 182 | 173 | 155 | 158 | 147 | 141 |
| Average short haul international | 104 | 102 | 88 | 90 | 89 | 95 | |
| Average long haul international | 119 | 120 | 111 | 105 | 101 | 104 | |
A summary of trends in efficiency for different transport modes is presented below.
Road transport
Petrol cars were more emitting than diesel cars in 2017, although the gap has narrowed compared to previous years. Hybrid cars were substantially more efficient, with emissions of 36.5% and 34.1% less than petrol and diesel cars, respectively.
Improvements in fuel efficiency of cars between 2012 and 2017 were slightly offset by a decrease in the average number of car occupants. The average number of travellers per car decreased from 1.513 in 2012 to 1.500 in 2017,[8] which meant that reductions in emissions per passenger kilometre were proportionately less than reductions in emissions per car kilometre.
Rail
Other than coach travel, rail was the most efficient means of transport in 2017. Both national rail and light rail and tram services saw reductions in average emissions per passenger kilometre between 2012 and 2017. A number of factors may have influenced this, including increased electrification of the rail network, improved fuel efficiency of trains, and increased capacity of train services.
Aviation
Despite a reduction in average emissions per passenger kilometre of 22% between 2012 and 2017, domestic aviation remained the least efficient means of travel in 2017. Since a large proportion of aviation emissions is due to take-off and landing, international aviation is on average more efficient than domestic aviation per passenger kilometre.
Passenger ferries
Ferry travel saw little change in efficiency between 2012 and 2017, with average emissions of 116 gCO2e/pkm throughout the period.