Traffic Operations and Management

The Cell Transmission Model. Part I: A Simple Dynamic Representation of Highway Traffic

Carlos Daganzo
1993

This paper presents a simple representation of traffic on a highway with a single entrance and exit. The representation can be used to predict traffic's evolution over time and space, including transient phenomena such as the building, propagation and dissipation of queues. The easy-to-solve difference equations used to predict traffic's evolution are shown to be the discrete analog of the differential equations arising from a special case of the hydrodynamic model of traffic flow. The proposed method automatically generates appropriate changes in density at locations where the...

Technical Description of NETCELL: General Framework and Data Structure

Lin, Wei-Hua
Carlos Daganzo
1994

This technical note presents a prototype of a freeway network simulation program, NETCELL, currently under development. NETCELL is based on the cell transmission model which captures the dynamic evolution of multicommodity traffic over a freeway network with three-legged junctions in a way that is consistent with the hydrodynamic theory of highway traffic. The report discusses implementation of the prototype program in detail, including cell representation for a freeway network with three- legged junctions data and file structures, inputs and outputs, and some key algorithms...

Effect of Modeling Assumptions on Evolution of Queues in a Single Corridor

Carlos Daganzo
Lin, Wei-Hua
1994

A qualitative description is presented of queuing patterns under an idealized scenario analogous to the evolution of traffic congestion during the morning peak hour in a long corridor leading to a single destination. The simplicity of the scenario allows the results to be verified independently by hand. Initially the corridor is assumed to consist of a single freeway. Traffic is generated at the freeway's many on-ramps during a short period and then is assumed to subside. Capacity limitations create queues on the ramps and the freeway, whose evolution is then described. A special...

The Cell Transmission Model: Network Traffic

Carlos Daganzo
1994

This paper shows how the evolution of multicommodity traffic flows over complex networks can be predicted over time, based on a simple macroscopic computer representation of traffic flow that is consistent with the kinematic wave theory under all traffic conditions. After a brief review of the basic model for one link, the paper describes how three-legged junctions can be modeled. It then introduces a numerical procedure for networks, assuming that a time-varying origin-destination table is given and that the proportion of turns at every junction is known. These assumptions are reasonable...

The Cell Transmission Model: A Dynamic Representation of Highway Traffic Consistent with the Hydrodynamic Theory

Carlos Daganzo
1994

This paper presents a simple representation of traffic on a highway with a single entrance and exit. The representation can be used to predict traffic's evolution over time and space, including transient phenomena such as the building, propagation, and dissipation of queues. The easy-to-solve difference equations used to predict traffic's evolution are shown to be the discrete analog of the differential equations arising from a special case of the hydrodynamic model of traffic flow. The proposed method automatically generates appropriate changes in density at locations where the...

A Continuum Theory of Traffic Dynamics for Freeways with Special Lanes

Carlos Daganzo
1995

This paper presents a generalized theory of kinematic waves for freeways with two vehicle types and a set of lanes reserved for one of the vehicle classes. The theory is not restricted to freeways on which the special lanes are clearly identified by signs and pavement markings; e.g. for high occupancy vehicles. It may also apply if the restrictions are self-imposed, such as would occur on a freeway segment upstream of a busy off-ramp where the existing traffic naturally avoids the ‘far-side’ lanes. Of particular interest are oversaturated time periods because the original theory of...

The Nature of Freeway Gridlock and How to Prevent it

Carlos Daganzo
1995

An Informal Introduction to Transportation and Traffic Operations

Carlos Daganzo
1995

Effects of Queue Spillovers in Transportation Networks with a Route Choice

Carlos Daganzo
1996

Dymanic Traffic Assignment With Queues For ATIS : Final Report For Project MOU 90

Carlos Daganzo
1996

This document reports on a project whose overall objective was to develop a traffic flow model capable of predicting the evolution of multicommodity (multiple destination) network traffic flows consistent with the hydrodynamic theory of traffic flow. The output of this research should enhance the realism of modeling capabilities in representing traffic flows and especially physical queues. This should provide a solid platform for the evaluation of Intelligent Transportation Systems (ITS) improvements, environmental impacts, and dynamic control strategies. In particular, it holds...