Traffic Theory

Network Representation, Continuum Approximations and a Solution to the Spatial Aggregation Problem of Traffic Assignment

Daganzo, Carlos F.
1980

This paper complements the preceding one, which showed how one could modify equilibrium traffic assignment algorithms for networks with many centroids. In this one it is shown how one can substitute centroids by zones with continuous population densities. The technique, which is mathematically guaranteed to approximate a flow pattern in accordance with Wardrop's user equilibrium criterion, requires some geometrical calculations which can be handled off-line. With the suggested approach, it is possible to represent the spatial distribution of trip ends more realistically and this allows...

Estimation of Gap Acceptance Parameters: Sequential vs. Simultaneous Method in Light Poisson Traffic

Han, A.F.
Daganzo, Carlos F.
1982

Derivation of Delays Based on Input-Output Analysis

Daganzo, Carlos F.
1983

In a recent paper Michalpoulos and Pisharody (1981) contend that traditional input-output analysis results in substantial overestimation of delays, and they develop an alternate, more laborious, calculation method. This premise is incorrect since input-output analysis is nothing more than a simple accounting method, which by definition gives exact results. It should give results consistent with the more laborious method proposed by those authors.

The Break-Bulk Role of Terminals in Many-to-Many Logistic Networks

Daganzo, Carlos F.
1987

This paper examines the structure of many-to-many logistics networks. Using as little data as possible, it attempts to answer macroscopic questions such as: How many terminals should be used? Should they be used at all? What should be the frequency of service? Although such a problem could be formulated with a large number of parameters and data, we show that near-optimal network structures can be characterized by two dimensionless constants which can be determined from the data (e.g., from the value of the items carried, the number of origins, the size of the service region, etc …). The...

Some Bounds for the Vehicle Routing Problem

Daganzo, Carlos F.
1989

Some Properties of Polling Systems

Daganzo, Carlos F.
1990

This paper examines the properties of single server queueing systems with customers of several types, where the server rotates its effort among the customer classes and serves all the customers that have accumulated for each class before moving on to the next. The paper shows that expressions for the first two moments of the queue lengths, and for the mean waiting times, can be developed from two simple properties of the arrival and service processes. The properties, which include existing models as special cases, seem plausible descriptors of the complex arrival and service processes that...

Restricting Road Use Can Benefit Everyone

Daganzo, Carlos F.
1992

This paper seeks congestion reduction schemes that do not penalize anyone. It shows that a combination of rationing and pricing (unlike congestion pricing alone) can benefit everyone even if the collected revenues are not returned to the population. The simple conditions under which this is possible are identified. Little data are needed to choose a proper policy. Examples are given.

Restricting Road Use Can Benefit Everyone, Part II: Time-of-Day Restrictions that Encourage Earlier Arrivals

Daganzo, Carlos F.
1992

This research considers a less restricting rationing scheme where a restriction would mean that passage through the bottleneck is banned after a certain time of the day (e.g. the start of the rush hour) but not before that time. Conservatively, we assume that the ban remains in force even after the conclusion of the rush, although in practice one would like to terminate it earlier. (This assumption limits the benefits that can be gained from control as it discourages people from delaying their arrival in order to avoid the queue.) Despite this inefficiency, the scheme is shown to...

The Spatial Evolution of Traffic Under the Two Wave Speed Assumption: A Shortcut Procedure and Some Observations

Daganzo, Carlos F.
1993

This paper describes the behavior of traffic in a homogeneous highway according to the hydrodynamic theory, in the special casewhere the flow-density relationship is triangular; i.e. when only two wave velocities exist. It presents an exact formula thatpredicts the vehicle that would be found at position x at time t, given the locations of all the vehicles at time zero. The formula, which does not require identification of the vehicle positions at intermediate times, automatically accounts for the creation and dissipation of any shocks. It can be used to calculate system performance...

Moving Queues in Freeway Traffic Networks

Daganzo, Carlos F.
Lin, W. H.
1993

This paper presents the basic building block and some illustrations of a computer program that is currently being developed to predict the behavior of freeway traffic with a macroscopic model. The program, which keeps track of traffic destinations, is based on an approximation of the hydrodynamic theory of traffic flow in which time and space are treated as discrete variables. The program automatically tracks shocks and acceleration waves, and can realistically locate the front and rear end of moving queues within every link. The basic building block is illustrated by means of a...