Search results for " queues"
showing 4 items of 4 documents
A model to evaluate heavy vehicle effect in motorway traffic flow
2017
Highway operating conditions are also determined by interactions between passenger cars and heavy vehicles in the flow. Therefore, a suitable model which describes and predicts the heavy vehicle effect can be useful to achieve more realistic criteria to evaluate the Level of Service (LOS) for infrastructures in the uninterrupted flow. After reviewing briefly the models available in literature to take account of the effects on operating conditions due to heavy vehicles, the paper examines some traffic data analysis of the Italian A22 motorway and later presents a closed-form traffic model for heavy vehicles via the queuing theory. Some applications of this model are displayed for operational…
Turbo-Roundabouts: a Model to Evaluate Capacity, Delays, Queues and Level of Service
2012
A turbo roundabout is a particular type of roundabout where entering and circulating lanes are bounded by traffic signs and by non-mountable curbs. The physical separation between lanes, both at entries and on the ring, helps to prevent side collisions crossing the roundabout. The main advantages of turbo roundabouts are: i) reduction in the number of potential conflict points; ii) lower speed of vehicles passing through the intersection; iii) safety conditions at the intersection due to lower risk of side-by-side accidents. These aspects make turbo-roundabouts more appropriate than roundabouts when a higher level of safety has to be guaranteed, particularly in presence of relevant pedestri…
The design of waiting and storage areas to improve the efficiency of the marine intermodal terminals
2013
The correct sizing of storage areas in the port areas is aimed to optimizing the management of intermodal transport and to ensure efficiency and functionality to the entire port system. In this paper is proposed a simulation model for design the port storage areas taking into account many parameters like: the service time, the randomness of the arrivals process, the storage capacity in terms of TEU that can be stored (and handled) in the unit of time. The capacity of the terminal warehouse is determined by the interrelation between fixed and static parameters in the short period which are: i) the extension of the storage area; ii) the height of the overlapping batteries of container (define…
A Time-Non-Homogeneous Double-Ended Queue with Failures and Repairs and Its Continuous Approximation
2018
We consider a time-non-homogeneous double-ended queue subject to catastrophes and repairs. The catastrophes occur according to a non-homogeneous Poisson process and lead the system into a state of failure. Instantaneously, the system is put under repair, such that repair time is governed by a time-varying intensity function. We analyze the transient and the asymptotic behavior of the queueing system. Moreover, we derive a heavy-traffic approximation that allows approximating the state of the systems by a time-non-homogeneous Wiener process subject to jumps to a spurious state (due to catastrophes) and random returns to the zero state (due to repairs). Special attention is devoted to the cas…