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The holy trinity of walking, cycling and public transport usually springs to mind when the term ‘sustainable transport’ is mentioned, whilst private vehicles sits at the polar opposite. Transport Canada identifies the goal of sustainable transport as “[ensuring] that environment, social and economic considerations are factored into decisions affecting transportation activity” (VTPI, 2017). However, with transport accounting for approximately 33% of all carbon dioxide emissions in the UK last year (BEIS, 2019), it forms the assumption that the UK tends to neglect the environmental component in what classes transport as “sustainable”, and it cannot be underestimated how important prioritising more environmentally sustainable modes of travel is moving forward.

The largest contributor towards the 33% of transport emissions in the country is passenger cars, making up 54% of transport related emissions (Element Energy, 2015), and with only 0.2 million out of the 39.4 million registered cars in the UK last year being ultra-low emissions vehicles (ONS, 2019), cars are clearly the least favourable day-to-day mode of transport in achieving the goals for sustainable transport. So what are the other options? And how can we do better?

Congestion emphasises high reliance on cars (Source: Tute, 2019)

In a lecture on sustainable transport systems, Alan Wann presents some ‘good examples’ of sustainable transport systems around the world, all of which have efficient and highly frequented public transport systems, which include metro, trams and buses. In England, 4.36 billion journeys were made last year (Department for Transport, 2019) across 32,000 buses (Stagecoach, n.d.). However, in the rise of the condemning of the use of cars and private vehicles due to their contribution to greenhouse gas emissions, is it really sustainable to promote another mode of transport that does exactly that? Just because there are more people that can be transported by a bus than a car, is that enough to work towards sustainability, especially in the climate crisis we face today? Whilst it is easy to criticise car users for being responsible for the majority of carbon dioxide emissions every year, and applaud those who leave their cars at home to take the bus instead as they are thought to be more ‘environmentally aware’, let’s look at the facts.

Transport accounted for a third of emissions last year (Source: Green Guide Spain, 2014)

Between 2004 and 2010, carbon dioxide emissions from cars reduced from 75.3 million tonnes to 67.4 million tonnes, whilst those from buses actually increased from 4.5 million tonnes to 4.7 million tonnes (Future Travel, n.d.). Moreover, buses are thought to be much more sustainable than cars, but at 186 grams of carbon dioxide emissions per passenger kilometre, this only equates to 19 grams per passenger kilometre less than car emissions, at 205 grams of carbon dioxide per passenger kilometre (Future Travel, n.d.). When we calculate this per double decker bus which typically holds around 87 passengers (TfL,2014) that emits 16,182 grams of carbon dioxide per passenger kilometre at full capacity, compared to a 5 seater car at full capacity which emits 1,025 grams of carbon dioxide per passenger kilometre. Whilst this seems to work because of the vast difference between passenger quantity, what happens when it is late at night and that same bus is running with only 5 passengers on it? (Rowlatt, 2009) That roughly equates to 3,236 grams of carbon dioxide emissions per passenger kilometre, which is far more than the emissions from a car (Carbon Independent, 2019).

Less bus passengers does not equate to less CO2 emissions (Source: Heffer, 2018)

This of course does not take into account the marginal difference that extra weight makes on fuel consumption (Rowlatt, 2009) and therefore on carbon dioxide emissions, but the point I am making is – buses are a great option for sustainable transport when they are running at full capacity, particularly as most people that travel by bus will combine walking (to and from the bus stop) into their journey. However, with buses often running nearly empty – some in central London running at less than 70% full at peak times (Edwards, 2018) – does it really make sense to be running these buses every 3-4 minutes? (London Bus Routes, 2018)

Some buses run as frequently as every 3-4 minutes, yet run at less than 70% capacity even during rush hour (Source: London Bus Routes, 2018)

Perhaps the problem here is not the use of buses, but instead the frequency of buses that we are using. At what point does convenience override efficiency and environmental sustainability? Personally, I am guilty of taking the bus into university because it is more convenient, and if I miss the bus on the way to the bus stop I know the next one is only 10 minutes away. But if the next one wasn’t for another half an hour or even hour, I would definitely walk instead. For those that don’t have the option of walking, a less frequent bus service should result in buses operating at a higher capacity, therefore ironically, reducing the number of buses could actually improve sustainability. But maybe we should all just invest in bicycles or better walking shoes instead…


Carbon Independent (2019) Emissions from Bus Travel, Available at [Accessed on 18/12/19].

Department for Business, Energy and Industrial Strategy (2019) 2018 UK Greenhouse Gas Emissions, Provisional Figures, London.

Department for Transport (2019) Annual Bus Statistics: England 2017/18.

Edwards, T. (2018) Leaked documents reveal biggest bus shake-up for decades, BBC News.

Element Energy (2015) Quantifying the impact of real-world driving on total CO2 emissions from UK cars and vans, Cambridge.

Future Travel (n.d.) Statistics: Environment, Available at [Accessed on 17/12/19].

London Bus Routes (2018) Routes 38/N38, Available at [Accessed on 19/12/19].

Office for National Statistics (2019) Road Transport and Air Emissions, Available at [Accessed on 17/12/19].

Rowlatt, J. (2009) Why cars are greener than buses (maybe), BBC News.

Stagecoach (n.d.) UK Bus Industry – FAQs, Available at: [Accessed on 18/12/19].

Transport for London (2014) Route 66 switches to double decker, Available at [Accessed on 17/12/19].

Victoria Transport Policy Institute (2017) Sustainable Transportation and TDM, Available at [Accessed on 16/12/19].

3 responses to “(Un)Sustainable Public Transport?”

  1. Thank you, Karina, for such an insightful topic regarding the sustainability of public transport. As a frequent user of Stagecoach Bus Network in Newcastle-upon-Tyne, I can strongly relate to the issue you are raising. I would point out though that in order to prevent such CO2 emissions from cars and public transport, the UK Government (2018) have launched self-funded low emission transport scheme competitions, including Low Emission Bus Scheme (LEBS1), initiated by Department for Transport (DfT) and Office for Low Emission Vehicles (OLEV) in July, 2016. As for the period between 2017/18 and 2020/21, the Government have allocated £60 million for purchasing new electric buses and £40 million for supporting “local authorities’ retrofitting programmes for existing buses” (UK Government, 2018, p. 4).

    In order to further ‘electrify’ road transport system in the UK, the ‘Road to Zero’ strategy was introduced by the HM Government (2018) in July 2018. This strategy aims for 50% of new cars and 40% of new vans to be ultra-low emission by 2030. According to Unwin (2019b), ultra-low emission bus and taxi schemes are to play an integral part in achieving the aforementioned strategy. In terms of ultra-low emission taxi scheme, £6 million would be allocated for installing “300 rapid charge points and 46 fast charge points in 17 local authorities, including Greater Manchester, Brighton and Leicester” (Unwin, 2019a). In terms of ultra-low emission bus scheme, Unwin (2019b), referring to OLEV, states that among 19 local authorities, London’s (£7m), Manchester’s (£6.9m) and Cardiff’s (£5.7m) obtained the most funding, respectively. The funding has also been launched by Zenobe Energy company (£120m), which intends to “reduce the upfront cost associated with zero emission buses making the price similar to diesel buses and also lowering the total lifecycle cost by as much as 30%” (Barrett, 2019a). Currently, such cities as London, Manchester, Cardiff, York, Newport and Oxford have already announced their involvement in LEBS1, with the former already delivering 12 Low Emission Bus Zones (more than 200 electric buses) ahead of schedule (Barrett, 2019b).

    Maybe the future of sustainable public transport in the UK is not as bleak as it seems currently?!

    Barrett, T. (2019a) £120m electric bus fund launched for councils and bus firms. Available at: (Accessed: 18 January 2020).

    Barrett, T. (2019b) London to get ‘UK’s first’ fully electric bus routes. Available at: (Accessed: 18 January 2020).

    Barrett, T. (2019c) York bus firms awarded £1.6m ahead of Clean Air Zone. Available at: (Accessed: 18 January 2020).

    HM Government (2018) Road to Zero. Available at: (Accessed: 17 January 2020).

    UK Government (2018) Ultra-Low Emission Bus Scheme. Available at: (Accessed: 18 January 2020).

    Unwin, J. (2019a) UK government funds new taxi charge points. Available at: (Accessed: 18 January 2020).

    Unwin, J. (2019b) UK government funding to double ultra-low emission buses. Available at: (Accessed: 18 January 2020).

  2. Karina, thanks for such a thought-provoking perspective on public transport. I appreciate you questioning what sustainable public transport actually means. Accepting the fashionable notion that increasing provision is right, is easier than interrogating its credibility. Alan Wann’s lecture discussed the European Union Council of Ministers of Transport definition of sustainable public transport, as that which “allows the basic access and development needs of individuals, companies and society to be met safely and in a manner consistent with human and ecosystem health”[1], essentially considering economic, environmental and societal benefits.

    Buses worldwide are disproportional in their global emissions, mainly due to being diesel-based. In Bogota, buses comprising 5% of the city vehicles, produced 25% of its CO2 emissions, 40% of its Nitrogen Oxides and 50% of vehicle particulate matter[2]. Close exposure to these pollutants means severe effects for human health, but with only 300 air quality monitoring sites in the UK, the damage is hard to quantify[3]. The NHS spends 20% of its budget treating traffic-pollution related health problems[4]. Increasing the number of these vehicles may only exacerbate this pollutant problem, especially if they are running unnecessarily. If more people used public transport this would reduce car pollutants and segregated routes for cycling and walking, as in Copenhagen[5], may help mitigate this. Until then, consideration of whether half empty transport systems waste materials and unnecessarily release pollutants into our environments, which harm people and nature, needs addressing.

    London’s electric bus fleet is the largest in Europe, consisting of merely 2 bus routes[6]. Electrifying all vehicles means, raw elements need mining, energy intensive production occurs and operational electricity demand increases[7]. Chester and Horvarth suggest, in some cases, emissions from construction of public infrastructure are worse for the environment than the running systems[8]. New transport systems, such as HS2, have consequences, such as destruction of natural habitats and societies, but also benefits. Without considering the whole life process we can’t truly consider public transport sustainability.

    Suburban sprawl has created the ‘last mile problem’[9] and Wann discussed how people are willing to walk roughly 18 minutes for journeys[10]. To aid walkable cities and reduce unnecessary journeys, we should design, as Jane Jacobs[11] suggests, compact, mixed use, perhaps 20 minute, neighbourhoods. Urban Task Force set out principles linked to government policy and funding, combining collaborations with designers and citizens so that sustainable public transport, accessible to all, could be implemented[12]. Twenty years on this collaborative thinking still needs to be implemented.

    Stockholm has implemented ‘Beloved City’. Full delivery vans leave the depot and as they empty collect recycling, returning full of waste[13]. By carefully identifying combinable journeys, vehicles on the streets could reduce and increase efficiency. Perhaps late evening empty public transport, could carry goods around cities, collect waste or even become mobile care units. In a range of contexts, rural and urban[14], day and night, rush-hour or not, different options are appropriate. Maybe we all need to assess whether each journey is necessary or a luxury?

    [1] Wann, A. Sustainable Transport Systems. Newcastle University TCP8090: Principles and Practice of Urban Design, October 24, 2019

    [2] Wired. (2019) Why Electric Buses Haven’t Taken Over the World—Yet. Available at : (Accessed January 13, 2020).

    [3] Letters. The Guardian, World news. (June 25, 2019). Better Transport Options Are Key to Driving Us out of Our Cars | Letters. sec. Available at: (Accessed Januaruy 14 2019)

    [4] ibid.

    [5] HuffPost UK. (June 6, 2018). What Can The UK Learn From Copenhagen, The ‘Best City In The World’ For Cycling?. Available at: (Accessed January 16 2019).

    [6] Intelligent Transport. (June 5, 2019). The London Electric Bus Fleet Is the Largest in Europe. Available at: (Accessed January 18, 2020).

    [7] Monbiot, G. The Guardian. (August 1, 2017). The Car Has a Chokehold on Britain. It’s Time to Free Ourselves | George Monbiot. sec. Available at: (Accessed January 17, 2019).

    [8] Leibenluft, J. Slate Magazine. (November 25, 2008). Is It Always Greener to Take Public Transportation?.

    [9] Mallach, A. (2018). Elon Musk Is Wrong about Public Transport. But Transit in the US Is Still in Trouble. Available at: (Accessed January 17, 2020).

    [10] Wann, A. (2019). Sustainable Transport Systems. Newcastle University TCP8090: Principles and Practice of Urban Design, October 24, 2019

    [11] Jacobs, J. (2016) The Death and Life of Great American Cities. New Ed edition. Vintage Digital.

    [12] Force, T.U.T. (1999) Towards an Urban Renaissance, 1 edition. ed. London: Routledge.

    [13] BBC News. (2020). The Delivery Driver Who Takes Away Your Rubbish. Available at: (Accessed January 13, 2020).

    [14] Intelligent Transport. (2019). “The Balancing Act of Delivering Modern, Reliable and Sustainable Public Transport.” Available at: (Accessed January 16, 2020).

  3. The author explained the concept of sustainable transportation well, and made a certain analysis of the current situation in the UK. By consulting a large amount of data, comparing the actual carbon dioxide emissions of each person in the bus and the car, the comparison was obtained. The complete results also explain that when the night bus is not fully loaded, its emissions far exceed the emissions of cars. In fact, it can not be generalized in many cases. When we compare the transportation system, the bus can save more the road occupancy rate provides better protection for people’s travel and better solves the congestion situation, but many serious realities also deserve our constant discussion and resolution.

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