© Association for European Transport and contributors 2010 1
SIGNAL SETTING AND PATHS DESIGN FOR ROAD SUPPLY
MANAGEMENT IN EVACUATION CONDITIONS
Filippo A. Marcianò, Giuseppe Musolino
Antonio Polimeni, Agata Quattrone, Antonino Vitetta
Mediterranea University of Reggio Calabria
Dept. of Computer Science, Mathematics, Electronics and Transportation
alessandro.marciano@unirc.it , giuseppe.musolino@unirc.it
antonio.polimeni@unirc.it , agata.quattrone@unirc.it , vitetta@unirc.it
Abstract
In this paper a system of models for signal setting and paths design in
evacuation conditions is proposed. The system of models is developed in
order to respond to the necessity to integrate the design models present in
literature with traffic assignment models, taking into account the effects of
variation of supply and demand in terms of the signal setting and path choice.
1 INTRODUCTION
Transportation systems analysis and planning in emergency conditions
implies the necessity to tackle several issues. Among the others, the design of
traffic signals in junctions and the design of paths for emergency vehicles (e.g.
ambulances, civil protection vehicles, ....) on a road transportation network
have become increasingly relevant.
Nowadays signal setting is considered an effective strategy to increase
network capacity and to mitigate congestion phenomena. Current signal
setting design models and procedures do not provide solutions that take into
account users behaviour at path choice level in response to system
modifications. Few papers on signal setting design models present in
literature take into account users behaviour in response to signal setting
parameters modifications. Moreover, there are no specifications for road
transport systems in evacuation conditions: signal plans are empirically
defined or are defined by means of methods originally concieved to operate in
ordinary conditions.
Path design of emergency vehicles ranges from the design of a single path to
the design of a paths chain (routes design). Route design, commonly named
Vehicle Routing Problem (VRP), is present in literature but few papers present
design models taking into account congested networks.
Generally speaking, models and methods of literature seem not able to face
the VRP in emergency conditions where the assumptions of stationariety do
not hold, due to the relevant changes arising in supply and demand within the
reference period. The above changes affect the path choice dimension and,
therefore, the vehicle routing one, as a vehicle route is the result of a
combination of different paths.
From the above considerations, it emerged the necessity to integrate the
design models present in literature with traffic assignment models, in order to
take into account the effects of variation of supply and demand into the
vehicle routing definition.