Traffic Operations and Management

Steady State Conditions on Automated Highways

del Castillo, Jose M.
Lovell, David J.
Daganzo, Carlos F.
1995

This paper is concerned with technical investigations of traffic operations on automated highways. Estimates are made of the steady-state capacity of such freeways, paying particular attention to the effect of entry and exit maneuvers. The possibility of scheduling departing vehicles appropriately into platoons to minimize extraneous maneuvers is investigated. Characteristics of urban areas likely to be candidates for automated freeways are discussed, and some shortcomings of automated freeways, vis-à-vis conventional freeways, are pointed out. Finally, some areas of future research needs...

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

Daganzo, Carlos F.
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...

Effects of Queue Spillovers in Transportation Networks with a Route Choice

Daganzo, Carlos F.
1996

Determining the Spatial and Temporal Extents of a Queue Upstream of a Bottleneck

Daganzo, Carlos F.
Lovell, David J.
Lawson, Timothy
1996

A simple approach is presented for modifying an input-output (or queueing) diagram to measure the time and distance spent by vehicles in a queue. The fundamental diagram and input-output diagrams are described. The extent of queues in time and space also is described.

A Simple Physical Principle for the Simulation of Freeways with Special Lanes and Priority Vehicles

Daganzo, Carlos F.
Lin, Wei-Hua
Del Castillo, Jose M.
1997

This paper presents a simple physical principle that can be used to solve the kinematic wave problem for freeways with special lanes and priority vehicles. The principle is shown to yield the flows for all possible ‘Riemann problems’ arising in a homogeneous highway, so that its application in a simulation is equivalent to the Godunov ‘classic’ finite difference approximation method. The principle is appealing because its physical basis, unlike purely mathematical formulae, suggests a natural way in which boundary conditions for practical problems may be treated. Perhaps the IT principle...

The Netcell Simulation Package: Technical Description

Cayford, Randall
Lin, Wei-Hua
Daganzo, Carlos F.
1997

This report describes the NETCELL simulation package. NETCELL is a freeway network simulation program 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. NETVIEW is a graphical postprocessor for viewing NETCELL output files. This document discusses implementation of the programs in detail, including the cell representation for a freeway network with three-legged junctions, data and file structures, inputs and outputs...

Fundamentals of Transportation and Traffic Operations

Daganzo, Carlos F.
1997

Introductory chapters on “tools” cover topics such as graphical methods, optimization, probability, stochastic processes, statistics and simulation; these are complemented by application chapters on traffic dynamics, control, observation, and scheduled modes, where the fundamental ideas are presented in depth.

Causes And Effects Of Phase Transitions In Highway Traffic

Daganzo, C. F.
Cassidy, M. J.
Bertini, R. L.
1997

It is shown that all the phase transitions in and out of freely flowing traffic reported earlier for a German site could be caused by bottlenecks, as are all the transitions observed at two other sites examined here. Furthermore, all the evidence indicates that bottlenecks cause these transitions in a predictable way, and no evidence is found that stoppages (jams) appear spontaneously in free flow traffic for no apparent reason. The most salient phenomena observed at all locations are explained in terms of a simple theory specific to traffic.

Simple, Generalized Method for Analysis of Traffic Queue Upstream of a Bottleneck

Erera, Alan L.
Lawson, Tim W.
Daganzo, Carlos F.
1998

An approach is generalized for enhancing a standard input-output diagram to represent graphically the time and distance that vehicles spend in a queue upstream of a bottleneck. The approach requires the construction of a curve depicting the cumulative number of vehicles to have reached the back of the queue as a function of time. The original technique, described in a previous paper, is reviewed for bottlenecks with constant capacity and for those where capacity changes once. The approach is then generalized to allow multiple changes in bottleneck capacity, and the original assumption of a...

Queue Spillovers in Transportation Networks with a Route Choice

Daganzo, Carlos F.
1998

This paper explores some of the traffic phenomena that arise when drivers have to navigate a network in which queues back up past diverge intersections. If a diverge provides two alternative routes to the same destination and the shorter route has a bottleneck that generates a queue, one would expect that queue to stabilize at an equilibrium level where the travel time on both routes is roughly equal. If the capacity of the alternative route is unlimited then this network can accommodate any demand level. However, if the bottleneck is so close to the upstream end of the link that the...