Traffic Operations and Management

Traffic Delay at Unsignalized Intersections: Clarification of Some Issues

Daganzo, Carlos F.
1977

Investigations in this area have been directed at finding the delay to a motorist who arrives at an intersection and wishes to cross a high-priority traffic stream. In this paper two conceptual errors that have appeared in some past publications are identified and corrected.

The Uniqueness of a Time-dependent Equilibrium Distribution of Arrivals at a Single Bottleneck

Daganzo, Carlos F.
1985

Motorists going through a bottleneck during the morning rush hour have to time their departure times to ensure they arrive to work at a reasonable time. Traffic and congestion levels at the bottleneck depend on the motorists' work schedule and the disutility of unpunctuality. This paper shows that, under certain conditions, there is only one equilibrium order of arrivals; an order under which motorists do not have an incentive to jockey for position in the queue.

Modeling Distribution Problems with Time Windows: Part I

Daganzo, Carlos F.
1987

This paper shows how distribution problems with delivery time constraints can be modeled approximately with just a few variables. Its objective is neither to develop a scheduling algorithm nor an exact predictive method; rather, it is to illustrate some trade-offs and principles that can be used for planning and algorithm development. A workday is divided into time periods. Time windows are modeled by specifying the period in which a vehicle should visit each customer. (The companion paper explores scenarios where many customers do not specify a time window, and thus, it is advantageous...

Modeling Distribution Problems with Time Windows. Part II: Two Customer Types

Daganzo, Carlos F.
1987

This paper extends the results of a previous study concerning distribution with time windows. It is recognized that customers who do not need to be allocated to a time window should receive different service than the rest. Three strategies were studied to accomplish that: stratified service, discriminating service, and staggered and discriminating service. Of these, the last strategy yields the lowest local distribution distance per customer, a distance which can be less than half that for the strategy explained in the previous paper (joint service). Stratified service, however, can yield...

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...

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...

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

Daganzo, Carlos F.
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...

Technical Description of NETCELL: General Framework and Data Structure

Lin, Wei-Hua
Daganzo, Carlos F.
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...

Assembly System Design Principles and Tradeoffs

Daganzo, Carlos F.
Blumenfeld, D.E.
1994

This paper develops an analytical model to evaluate serial and parallel designs for an assembly system. The purpose is to identify when each design is cost-effective, using minimal data. The analysis shows that the design alternatives are based on a trade-off between labour and equipment utilization. Equations are derived for a simple system to illustrate this trade-off. Results indicate that the optimal trade-off depends simply on the ratio of labour to equipment costs. The trade-off analysis provides a first step towards establishing basic principles for assembly system design.