Project: Technologies for Advanced Co-operative Driving (TACO)

Reference: CSU 28/4/49

Last update: 04/08/2003 08:48:35


To study the operations of road convoys.


Research will concentrate on the development of a robust strategy for the safe operation of convoys and microscopic modelling of such convoys and in particular the merging/ demerging process. A secure short-range radio for data transfer between vehicles will also be developed.


University of Southampton
Transportation Research Group, Dept of Civil and Environmental Engineering, Southampton, Hampshire, SO17 1BJ

Central Research Laboratories Ltd
Dawley Road, Hayes, Middlesex, UB3 1HH
0208 848 6488

Contract details

Cost to the Department: £117,516.00

Actual start date: 01 June 1997

Actual completion date: 01 July 1999

Summary of results

  1. The convoy operations studied in this project do not rely on the existence of roadside supporting systems for inter vehicle communications. Convoy-equipped vehicles have two-way communication systems, which enables them to communicate with those to the front and rear, as well as vehicles in adjacent lanes when the vehicle merges to ord de-meges from the convoy lane, or changes speed.

    Algorithms for convoy operations and merging/de-merging process between two adjacent lanes have been indentified, developed and simulated in the FLOWSIM model. Vehicle operations can be simulated for three different levels of automation, unsupported, autonomous cruise control (ACC) equipped, and full convoy operation equipped. The potential impacts of convoy operations on motorway traffic have been explored by simulation using FLOWSIM model.

    Impacts of convoy operations have been examined using four observable factors of major concern to infrastructure owner/operators and the general public. These are i) traffic flow stability, ii) capacity, iii) journey time, and iv) the merge and de-merge efficiences. The simulation results show that:-

    i) Convoy operation
    - can significantly improve traffic flow stability for all motorway traffic, and this will lead to the improvement on safety, comfort, energy consumption and environmental impacts,
    - may significantly increase road capacity by more efficient use of convoy lane, and
    - can reduce journey time significantly for convoy traffic. It also reduces journey time for overall traffic when there is a certain percentage (e.g. 30%) of vehicles in convoy lane.

    ii) Efficiency of merging/de-merging decreases as demand and percentage of merging and de-merging traffic increases. In high demand and high percentage merging and de-merging cases, warning or supporting system may be required to help de-merging vehicles to leave the convoy lane without missing their destinations. Further research on alternative supporting systems for merging/de-merging is important to a potential deployment of convoy operations.

Departmental Assessment Status: Project completed prior to implementation of Departmental Publication Scheme.