Toggle Main Menu Toggle Search

Open Access padlockePrints

The use of the speed-flow curve to demonstrate the effect of new technologies

Lookup NU author(s): Professor Margaret Carol Bell CBE


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


This paper develops the concept of road capacity, from the traffic, emissions and climate change perspective. It demonstrates how traffic management and control technologies manage to move more traffic, more smoothly as they have become more sophisticated. However, our motorways and urban networks continue to experience recurrent congestion. As a consequence, increase in pollutant emissions, including climate change gases, are respectively increasing health risk and threatening the planet. Results of research are presented to demonstrate the role of driver behaviour and vehicle technologies in reducing emissions by smoothing flows and reducing source emissions. However, results of real-world tailpipe emissions are used to demonstrate why there need for radical changes in people’s attitudes to the use of public and private transport as well as the design and operation of transport infrastructure. There is a need to move away from the traditional approach of optimising networks as traffic systems but instead to minimise performance measures associated with effective movement of people and goods. Also, in the near future, due consideration needs to be given to controlling the demand for travel by car in order to meet air quality and noise targets set by the European Commission. However, if climate change issues are to be addressed, a dramatic reduction in personal travel and freight miles, along with investment in and use of sustainable transport systems is essential The purpose of this presentation is to provoke discussion with regard to the use of the speed flow curve as an aid to the understanding and design of possible ‘futures’.

Publication metadata

Author(s): Bell MC

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Proceedings of the 40th University Transport Studies Group Conference

Year of Conference: 2008

Publisher: UTSG