ITS Berkeley

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.

Technical and Economic Viability of Automated Highway Systems: Preliminary Analysis

del Castillo, Jose M.
Lovell, David J.
Daganzo, Carlos F.
1997

Technical and economic investigations of automated highway systems (AHS) are addressed. It has generally been accepted that such systems show potential to alleviate urban traffic congestion, so most of the AHS research has been focused instead on technical design and implementation issues. It is demonstrated that, despite making a number of assumptions that are favorable to AHS, the actual viable implementation opportunities for AHS are scarce, and that most existing congested urban areas can be disqualified on the basis of at least one criterion developed herein. Technical investigations...

Using Input-Output Diagram To Determine Spatial and Temporal Extents of a Queue Upstream of a Bottleneck

Lawson, Tim W.
Lovell, David J.
Daganzo, Carlos F.
1997

A simple approach is described for modifying an input-output (or queue-ing) diagram to measure the time and distance spent by vehicles in a queue in a much simpler and self-serving manner than a time-space diagram. The graphic technique requires construction of a curve depicting the cumulative number of vehicles to have reached the back of the queue as a function of time, but, as indicated here, the technique can be easily automated with a spreadsheet. The technique is applied to the simple case of a constant departure rate from a bottleneck and to the slightly more general case of a...

A Simple Detection Scheme for Delay-Inducing Freeway Incidents

Lin, Wei-Hua
Daganzo, Carlos F.
1997

This paper describes a freeway incident detection scheme that does not rely on complicated theories. The procedure compares the occupancy information recorded by two neighboring loop detectors to determine whether an incident has occurred in the intervening segment, using a recipe that is directly related to an intrinsic property of delay-inducing incidents. The method, which can also signal the termination of a detected incident, assumes that any significant bottlenecks are located outside the segment in question: i.e. that the segment is “homogeneous”. Independent of complicated theories...

A Continuum Theory of Traffic Dynamics for Freeways with Special Lanes

Daganzo, Carlos F.
1997

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...

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...

An Enhanced Cell-Transmission Rule for Traffic Simulation

Daganzo, Carlos F.
1997

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.