Research Article

Urban Freight Management with Stochastic Time-Dependent Travel Times and Application to Large-Scale Transportation Networks

Table 1

Notations and variables.

TypeSymbolDefinition

Objective 
function 
quantities
The number of vehicles out for service
STTotal schedule time
TTTotal travel time
WTTotal waiting time
SVTTotal service time

SetsSet of starting nodes of all vehicles
Set of end nodes of all vehicles
Set of all customer nodes
Set of starting nodes and customer nodes
Set of customer nodes and end nodes
Set of all nodes
Set of all customers
Subset of set
Set of links that are present in the networks

Inputs and parametersThe number of time intervals
Time interval
An infinite number
Service time of customer node
Delivery demand of customer node
Time window of depot
Time window constraint of customer node
Capacity of vehicle

Decision variablesVehicle’s arrival time at node
, if any vehicle occupies at time ; otherwise
Travel times of the optimal path from customer node i to customer node j at departing time interval
, if vehicle departs from customer node to customer node at time interval ; otherwise
, if customer node is visited by vehicle ; otherwise,