EPSRC logo

Details of Grant 

EPSRC Reference: EP/D506840/1
Title: Dynamic analysis of road traffic flow
Principal Investigator: Heydecker, Professor B
Other Investigators:
Researcher Co-Investigators:
Dr J Addison
Project Partners:
Highways Agency
Department: Civil Environmental and Geomatic Eng
Organisation: UCL
Scheme: Standard Research (Pre-FEC)
Starts: 01 August 2005 Ends: 31 August 2007 Value (£): 142,923
EPSRC Research Topic Classifications:
Transport Ops & Management
EPSRC Industrial Sector Classifications:
Transport Systems and Vehicles
Related Grants:
Panel History:  
Summary on Grant Application Form
An aim of traffic management is to promote effective use of the road system for the benefit of the community as a whole. Motorway roads can provide safe and convenient routes for private and commercial vehicles, and managing motorways so that they operate well is therefore important. Sometimes, the flow of traffic on motorways changes suddenly from smooth and quick to stop-go: this kind of change is known as flow breakdown . Flow breakdown causes congestion and delay, resulting in the inconvenience of longer and less reliable journey times, with the additional risk of rear-end collisions as vehicles enter the congested region. Flow breakdown can happen because of extra traffic joining a motorway, or because of incidents, uphill sections or bends that reduce capacity. But sometimes in heavy traffic, flow breakdown happens spontaneously and for no reason other than inherent instability: this is described as spontaneous flow break down , and can be an important cause of congestion. We are interested in measuring and understanding his kind of flow breakdown, and in investigating the effect of certain traffic management measures in postponing or even avoiding it.When traffic on a motorway is heavy, flow can be improved by managing the traffic entering it or already on it. One possibility for this is to reduce the speed limit so that vehicles can travel closer together whilst maintaining safety: the traffic then flows more smoothly. Using variable speed limits to slow the fastest vehicles in this way can avoid flow breakdown and so reduce the journey time for most vehicles provided that it is done when the conditions are appropriate. Making the best use of this kind of traffic management measure requires a good understanding of the behaviour of traffic, especially when flow is heavy and susceptible to spontaneous breakdown. Mathematical models of traffic flow based on this understanding can be used to support decision making on how to manage motorway traffic at busy times.Mathematical models of traffic flow already exist that describe the formation and clearance of traffic queues, and the effect that this has on the journeys of vehicles that pass through the congested region. These models are helpful in investigating congestion that is caused by road works or incidents that reduce capacity, or when flow entering a motorway takes the total flow beyond capacity. However, current forms of these models do not describe well the kind of spontaneous flow breakdown that is the focus of this project because they represent unstable traffic behaviour appropriately. In this project, we will develop traffic models that can describe spontaneous flow breakdown effectively as well as representing the effects on this of traffic management measures such as variable speed limits. To do this, we will investigate circumstances in which spontaneous flow breakdowns occur, the effect of speed limits on this, and their combined effect on motorway traffic flow.Our investigation will be draw on detailed information on traffic flows and other relevant influences such as speed limits, weather and light conditions that are recorded for the motorway network by the Highways Agency. This will enable us to investigate spontaneous flow breakdown in detail, and the effects of traffic management measures such as variable speed limits on this. We are particularly interested in comparing between conditions in which variable speed limits were used and those on which they were not, to examine the effect that they have on traffic behaviour under otherwise similar conditions. Using our findings from this, we will then be able to select and develop mathematical models that are capable of representing this kind of traffic behaviour and measure to management it. These models will ultimately be used to help managers to make informed decisions on how best to manage traffic on busy motorway roads.
Key Findings
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Potential use in non-academic contexts
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Description This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Date Materialised
Sectors submitted by the Researcher
This information can now be found on Gateway to Research (GtR) http://gtr.rcuk.ac.uk
Project URL:  
Further Information:  
Organisation Website: