A Multi-Modal Transport Model for Integrated Planning
presented by Dr. Markus Friedrich, at the 8th World Conference on Transport Research, Antwerp 1998
PTV AG Stumpfstr. 1 D-76131 Karlsruhe Tel.: +49-721-9651-0 Fax: +49-721-9651-299 Email: firstname.lastname@example.org
A MULTI-MODAL TRANSPORT MODEL FOR INTEGRATED PLANNING
PTV AG D-76131 Karlsruhe, Germany
Abstract Transport models are applied to support the planner in the process of planning and decision making. Models attempt to replicate the system of interest and the system’s behaviour. The presented model considers the transportation system with its interactions between the several supply systems and the demand system. The transport model, implemented in a software product called VISUM, consists of • a network model describing the spatial and temporal structure of the supply systems, • a demand model simulating activities and generating trip chains, • routing and assignment models to determine service quality and route choice. The paper focuses on the requirements of a multi-modal transport model and • gives an overview of an activity-based demand model, • presents the structure of a network model integrating various modes and supply systems, • shows methods which support the design process and assist the planner in finding new solutions, • discusses multi-modal assignment procedures.
INTRODUCTION Understanding and solving transport problems is a process which generally starts with an analysis of the current state (Figure 1) in order to deduct deficiencies. The analysis of the current state is followed by a design process which can be partitioned into four steps (Figure 2): • development of a solution, • determination of impacts, • evaluation of impacts, • analysis of deficiencies. These four steps constitute a cyclic process which continues until a satisfactory solution meeting the planning objectives is achieved.
Current transport system
Development of a solution
Determining the impacts of current system • performance indicators • operational indicators
Determining the impacts of solution • performance indicators • operational indicators
Evaluating the impacts of current system
evaluating the impacts of solution
Deduction of deficiencies
analysis of deficiencies
Figure 1 - Analysis of the current state
Figure 2 - Design process
Transport models are applied to support the planner in this process of planning and decision making. These models attempt to replicate the system of interest and the system’s behaviour. The presented model considers the transportation system with its interactions between the several supply systems and the demand system. The transport model, implemented in a software product called VISUM, consists of a demand model, a network model and a set of impact models (Figure 3): • The demand model contains the travel demand data. It simulates activities and generates trip chains to estimate and forecast mode-specific origin-destination matrices for behaviourally homogeneous population groups. Travel demand estimates are derived from structural land use data and service indicators determined by the impact model. Because the demand model describes the traveller’s choice between various modes of transport it may be labelled "multimodal". • The network model contains the relevant data of the supply systems describing their spatial and temporal structure. It consists of traffic zones, nodes and public transport stops, links and public transport lines. Since the network model integrates private and public transport modes it may be labelled "pluri-modal". The impact models take their input data from the demand model and the network model. VISUM integrates different impact models to analyse and evaluate a transport system. A user
model simulates the travel behaviour of public transport passengers and car drivers. Based on routing and assignment models it calculates traffic volumes and...