Elvezia Maria Cepolina

A methodology for defining building evacuation routes

This paper concerns an innovative methodology aimed towards specifying the best set of evacuation routes in a given scenario—where a scenario is characterised by the enclosure geometry, the population’s capabilities and the population distribution within the building. The best set of evacuation routes is assumed to be the one which minimises the movement time of the last evacuee. The problem faced is an optimisation problem where the cost function to be minimised is the last evacuee’s movement time and the research space is defined by all the possible sets of evacuation routes in the given scenario. As this cost function could be a multipeak function and since the research space is discrete and extremely large, a random search algorithm has been adopted. Given a set of evacuation routes, the proposed methodology models the evacuation over time with the aim of finding the movement time of the last evacuee. The modelling of the evacuation over time has to obey two criteria. First, as it is embedded in the optimisation process and it has to be repeated a very high number of times (potentially for each possible set of evacuation routes), the computational cost is a critical issue: therefore the model has to be ‘synthetic’ and microscopic models result not suitable. Secondly, the model cannot neglect flight behaviour and crowd crushes: therefore the need for a Dynamic Network Loading model which allows to keep track of the location of moving queues in the network, to predict spillbacks and dissipation and to model capacity drop due to clogging effects as well. The overall model has been implemented in an object-oriented simulator that allows analysis of large multifloor buildings. The simulator has been applied to an illustrative problem of evaluating the best set of evacuation routes for a school: the application results are reported in the paper. The methodology application field is straightforward evacuation, i.e., assuming that no fire exists. In this context, the best set of evacuation routes is chosen off-line and the building occupants could be trained on the escape routes they have to follow from their origin rooms to the exit.

Urban car sharing: An overview of relocation strategies

Traditional car sharing systems are round trip shared vehicle systems and require advance reservations. The advances of GPS, communication techniques and vehicle automation allow us to improve car-sharing systems and to provide users with greater flexibility. As it concerns reservation, new car sharing systems offer users open-ended reservation and/or instant access. As it concerns the trip topology, new car sharing systems are multiple station shared vehicle systems (MSSVS). Round trips still occur in this type of system; however there are a large number of one-way trips made between the multiple stations. Operating an MSSVS is much more difficult than operating a round trip shared vehicle system. The problem is that the system can quickly become imbalanced with respect to the number of vehicles at the multiple stations. A review of user-based and operator-based relocation strategies is provided in the paper, as well as some details about some new possible car sharing systems, where vehicles are fully automated and can be accessed from any point within the intervention area.

Microscopic simulation of pedestrians in accessibility evaluation

Evaluation of accessibility is of increasing importance to the design of the public realm – including both the built and moving environments and particularly the interface between them. This is of particular relevance to people who are living on the ‘margins of accessibility’, for example, elderly or disabled people. This paper discusses the interactions between a person, the environment and the activities they wish to pursue, and proposes a model that incorporates the concept of ‘capabilities’. The paper then describes how the systematization of these concepts could be tested by incorporating them in a microscopic simulation model of pedestrian activity. A worked example is used to demonstrate how the conceptual approach could yield consistent results under these circumstances. The paper concludes that the conceptual model provides a good basis for the evaluation of accessibility and that the microscopic simulation model incorporating these characteristics would be a useful way of testing pedestrian–environment interactions.

Innovative strategies for urban car-sharing systems and a simulator to assess their performance

In this paper, three innovative car-sharing systems for urban areas are proposed, based on fleets of individual intelligent vehicles with three service characteristics: instant access, open-ended reservations and one-way trips. These features provide high flexibility but create an uneven distribution of vehicles among stations. Therefore, relocation of vehicles must be performed. Three different system procedures are proposed: in the first system, relocations are performed by users; in the other two, vehicles relocate automatically, thanks to their automation. In the first two systems, vehicles are accessible only at stations, whereas in the third they are also accessible along roads. In order to provide transport managers with a tool to test systems in different realities, an object-oriented simulator is developed. The simulation provides outputs of system performance, in terms of user waiting times and system efficiency. The proposed systems are simulated for the city of Genoa, in Italy, and a comparative analysis is presented.

A new user based system for historical city centres

The paper concerns the conceptual design of a new car-sharing system for historical city centres and the simulation of the system for the historical city centre of Genoa. The application fields of the system are historical city centres characterised by narrow streets and interactions with high pedestrian flows. The proposed transport system is based on a fleet of Personal Intelligent City Accessible Vehicles (PICAV). The following specific services are provided: instant access, open ended reservation and one way trips. Vehicles can be accessed and returned only at parking lots. These parking lots are placed in locations on the historical city centre border close to interchange points with public transportation. PICAV users are generated at these parking lots during the simulation. The authors assume the existence of a system supervisor who is in charge of addressing at least part of the PICAV users to specific parking lots. The supervisor, according with: the current waiting times at parking lots; the number of PICAV units available in each parking lot; the choice set Di of user i; assigns a parking lot to the user that has to be reasonable from both the point of view of the flexible user and of the fleet manager. An object-oriented simulator has been developed. Given an area, the localization of the PICAV parking lots, the fleet of PICAV units at each parking lot at the beginning of the simulation time and the PICAV transport demand, the simulator is able to provide the distribution of waiting times at each parking lot. This result enables one to dimension the fleet in order to have a given percentile of the distribution of user waiting times less than a given threshold.

An Electro–mobility System for Freight Service in Urban Areas

The paper introduces the problem of reducing impact of freight service trips in urban areas and presents the main design objectives, requirements, and steps of a new fully electric vehicle able to autonomously load and unload palletised or boxed freights. The subject is described under a multidisciplinary point of view integrating the mechatronic design, the efficient power supply system, the intelligent mobility control modules, the strategy for freight delivery planning, through a fleet of these vehicles, based on economic and behavioural modelling.