ITS Berkeley

Design of Multiple Vehicle Delivery Tours

Newell, G. F.
Carlos Daganzo
1984

Stochastic Network Equilibrium with Multiple Vehicle Types and Asymmetric, Indefinite Link Cost Jacobians

Carlos Daganzo
1983

This paper discusses a family of general link cost functions that can be used to model multimodal transportation network equilibrium problems. The family includes as a special case the currently favored family of monotonically increasing functions but does not necessarily have to have a symmetric or semi-definite Jacobian. In this way multimodal networks can be modeled somewhat more realistically. The paper also allows stochastic link costs for some or all the links and modes. It is shown that under mild conditions the equilibrium exists and is unique, but more importantly, that there is a...

Vehicle-Miles for a Freight Carrier with Two Capacity Constraints

Hall, Randolf W.
Carlos Daganzo
1985

The amount of freight that can be fit on a vehicle depends on the vehicle's weight capacity and volume capacity. In this paper mathematical equations are developed for evaluating the impact of weight capacity and volume capacity on total vehicle-miles. It is shown that the number of vehicle loads needed to carry a large amount of material is minimized when all vehicles are filled to the same capacity constraint. This is accomplished by mixing light items with heavy items in vehicle loads. Following this policy can reduce the number of vehicle loads and vehicle-miles. Under ideal...

The Distance Traveled to Visit N Points with a Maximum of C Stops per Vehicle: An Analytic Model and an Application

Carlos Daganzo
1984

The purpose of this paper is to develop a simple formula to predict the distance traveled by fleets of vehicles in physical distribution problems involving a depot and its area of influence. Since the transportation cost of operating a break-bulk terminal (or a warehouse) is intimately related to the distance traveled, the availability of such a simple formula should facilitate the study of more complex logistics problems. A simple manual dispatching strategy intended to mimic what dispatchers do, but simple enough to admit analytical modeling is presented. Since the formulas agree rather...

Checkpoint Dial-a-Ride Systems

Carlos Daganzo
1984

This paper presents a preliminary study of the feasibility of checkpoint dial-a-ride systems. Their cost-effectiveness is compared to that of fixed route systems with no transfers and door-to-door dial-a-ride systems. The results are derived for a simple routing strategy, and involve some simplifications which facilitate the comparisons. For high demand levels, the total cost per passenger for fixed route and checkpoint systems is very close. In fact, their optimal configurations are so alike, and the occurrence of route deviations is so rare, that fixed route systems should be preferred,...

Analyzing Trade-offs Between Transportation, Inventory and Production Costs on Freight Networks

Blumenfeld, Dennis E.
Burns, Lawrence D.
Diltz, J. David
Carlos Daganzo
1985

The purpose of this paper is to determine optimal shipping strategies (i.e. routes and shipment sizes) on freight networks by analyzing trade-offs between transportation, inventory, and production set-up costs. Networks involving direct shipping, shipping via a consolidation terminal, and a combination of terminal and direct shipping are considered. This paper makes three main contributions. First, an understanding is provided of the interface between transportation and production set-up costs, and of how these costs both affect inventory. Second, conditions are identified that indicate...

Physical Distribution from a Warehouse: Vehicle Coverage and Inventory Levels

Carlos Daganzo
Newell, Gordon F.
1985

This paper studies the costs involved in distributing items from a warehouse or depot to randomly scattered customers on a day-to-day basis. Two trade-offs are explored simultaneously. The first one arises because by accumulating large inventories at the depot it is possible to build more efficient distribution tours. This trade-off has already been explored for both distribution of goods (Burns et al., 1983) and passengers (Daganzo et al., 1977; Hendrickson, 1978). Another tradeoff, which involves the length of individual vehicle tours (Clarens and Hurdle, 1975), balances the inventory...

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

Carlos Daganzo
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.

Distribution Strategies that Minimize Transportation and Inventory Costs

Burns, Lawrence D.
Hall, Randolph W.
Blumenfeld, Dennis E.
Carlos Daganzo
1985

This paper develops an analytic method for minimizing the cost of distributing freight by truck from a supplier to many customers. It derives formulas for transportation and inventory costs, and determines the optimal trade-off between these costs. The paper analyzes and compares two distribution strategies: direct shipping (i.e., shipping separate loads to each customer) and peddling (i.e., dispatching trucks that deliver items to more than one customer per load). The cost trade-off in each strategy depends on shipment size. Our results indicate that, for direct shipping, the optimal...

Supplying a Single Location from Heterogeneous Sources

Carlos Daganzo
1985

This paper studies how items with different characteristics, and being demanded at different rates from a finite number of supply points, should be transported to a common destination. The items may differ in size and value, and the origins may differ in their spatial distribution, the kind of items they produce and the production rate. Depending on the application context, the common destination can represent a warehouse, a factory, a military base, a break-bulk terminal, a port or another kind of transportation terminal. Different kinds of items may call for separate transportation...