Effective use of excess capacity for low carbon urban transport futures

A reduction in emissions from transport is essential and requires a system wide approach, inclusive of technological and behavioural changes. Defining capacity in urban transport as the space through which transport demand can be met, the research explores where there is excess capacity in the system and how this could be used to reduce emissions. Capacity may be physical capacity in the roadspace or seats within vehicles, or temporal capacity, where there are fluctuations in the use of the system, such as peak and off-peak flows. This is complementary to the International Energy Agency (IEA)’s definition of urban transport energy efficiency as maximising travel activity whilst minimising energy consumption through a range of approaches and techniques. This paper proposes that interventions designed to enable behavioural change could reduce emissions by changing the way that the urban transport system is used. Drawing on the literature, this work demonstrates how effective use of excess capacity might be facilitated through measures such as smarter choices programmes and the application of intelligent transport systems (ITS). Case studies are provided as examples of ways that urban transport infrastructure can be adapted for more efficient use, including shared space projects and the ‘complete streets’ policy in New York City. The paper concludes by presenting the potential impacts of effective use of excess capacity for reducing urban transport emissions as demonstrated through the case studies.