Efficiency of transport modes

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 2012-2018.

Table 1: Fuel efficiencies for Scottish modes of transport

Sector	Mode and fuel	gCO2e/pkm
		2012	2013	2014	2015	2016	2017	2018
Road	Average petrol car[8]	133	131	128	128	129	124	123
	Average diesel car[8]	124	121	123	122	123	119	119
	Average hybrid car[8]	89	87	89	86	89	79	84
	Average petrol motorbike	119	119	120	120	120	117	115
	Average bus	112	112	110	109	102	103	101
	Average coach	29	29	29	29	29	28	28
Rail	National rail	58	49	47	45	49	47	44
	Light rail and tram	68	60	62	55	54	44	39
Ferry	Average foot and car passengers	116	116	116	116	116	116	113
Aviation	Average domestic flight	182	173	155	158	147	141	158
	Average short haul international	104	102	88	90	89	95	86
	Average long haul international	119	120	111	105	101	104	112

A summary of trends in efficiency for different transport modes is presented below.

Road transport

Coach fuel efficiencies have remained stable over the years and is the most carbon-efficient method of travel of the key transport modes presented here.

Diesel cars were more emitting than petrol cars in 2018, with the difference between petrol and diesel car emissions having reduced substantially over the years. Hybrid cars were more efficient, with emissions of 31.6% and 29.2% less than petrol and diesel cars, respectively.

Rail

Other than coach travel, rail was the most efficient means of transport in 2018. Both national rail and light rail and tram services saw reductions in average emissions per passenger kilometre between 2012 and 2018. 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 2018. Improvements in efficiency of aviation have meant that for some journeys it is now more efficient to travel by air than by ferry.