Transport contributes around a quarter of global CO2 emissions, a significant share, and is the only sector that has not seen emissions start to reduce. Generally this has been because improvements in efficiency and technology have been offset by ever increasing demand for transport. The challenges for developed and developing countries are quite distinct. In developed countries the challenge is to meet growing demand for transport through sustainable options and where the potential to expand roadways is limited and, in some cases, the peak in demand for private car travel may have been met. In developed countries, the challenge is to meet a basic need for transport services without increasing emissions, often trying to maintain a low share of private car ownership against the trend for increasing demand. In addition, in many developing country cities, the more pressing issue is poor air quality and the associated health risks from this. This article will focus on the developed country perspective, with the developing country perspective to follow in a later article.
One of the most obvious challenges for transport is congestion. Congestion increases emissions due to stationary traffic and the stop-start behaviour of queuing traffic. It may seem that the simplest solution to this problem is to build more roads but there are two problems with this: the first is that in many countries there simply isn’t space to build more roads in the most congested places as often the busiest roads are in densely packed cities where roads are constrained by buildings on either side; the second problem with building more roads is that as you expand the capacity of roads then the number of cars increases. For example, between 1970 and 1990 in California, USA, for every 10% increase in road capacity there was a 9% increase in traffic. Clearly an alternative solution is needed.
In the USA and Europe, emission standards are being placed on new vehicle fleets to try and reduce the environmental impact of car travel. The EU has a target of an average of 95gCO2/km from new cars in 2021 and Euro standards regulate emissions of NOx and other harmful pollutants. In the USA, the Corporate Average Fuel Economy (CAFE) standards have improved efficiency of passenger cars, with the 2014 efficiency at 34.2 miles per gallon. However, due to the structure of CAFE, this has actually incentivised an increase in light duty trucks which are not subject to the same standards which has had a perverse impact on emission reductions. There is a need for long term policy signals to drive innovation from car manufacturers and deliver substantial improvements in vehicle efficiency. This needs to be coupled with policies that can incentivise the uptake of electric vehicles and build the facilitating infrastructure for alternatively fuelled vehicles.
High quality, sustainable and affordable public transport options are an important part of the package needed to clean up our transport system. Moving large numbers of people over longer distances in fewer vehicles presents a more efficient option for transport and encouraging people to shift to these more sustainable choices is vital. In the UK, much of the rail infrastructure is overcrowded and is a long way behind the high-speed rail options available elsewhere in Europe. There are policies in place to improve this infrastructure in the coming decades but it is important that this is done in an affordable way that does not compromise other environmental objectives. Where effectively managed, high-speed rail can represent a real sustainable alternative, particularly where it can substitute domestic flights. An integrated public transport system will be essential in a cleaner transport future.
In developed countries, some are suggesting that ‘Peak Car’ has been reached, meaning that the growth in car ownership and distance travelled may have levelled off or be reducing. It is difficult to determine whether this is a change in the trends or a blip due to the economic crisis. But it appears that younger people are waiting to learn to drive due to the high costs of driving and the reduced need to own and run a car if you live in a city with alternative transport options available. It may be too early to tell if these trends can be maintained but capitalising on these early indicators of a shift could be a useful policy dimension for locking in sustainable transport choices.
There are a clearly a range of policy options available for developed countries to clean up their transport sector. There are also early indications of improvements through the potential peaking of demand for car travel and new technologies emerging from car manufacturers. But there is a need for stronger actions on the part of governments to force manufacturers to go further in improving vehicles, as well as delivering policy for public transport and alternative vehicles. It is essential that the transport sector, which contributes large volumes of CO2 to the climate crisis, as well as causing other significant environmental damage, is prioritised in order to deliver a low carbon, sustainable transport future.
Clare Linton is a researcher at the University of Leeds. Her research examines pathways to a sustainable transport future, exploring both technological and behavioural approaches to the challenge. She has worked with the Institute for Public Policy Research and holds an MSc in Climate Change and Policy from the University of Sussex. Follow on Twitter: @ClareLLinton and LinkedIn
*Cover image ‘Traffic’ by Michael Loke