Stefano Gori

An Urban Bus Network Design Procedure

This paper describes a coordinated process to configure a bus transit network with its set of lines and frequencies using heuristic approaches. In this context, the planning procedure consists of the following phases: in the first phase, the main skeleton of the network of the public transport system, not articulated in lines, is defined through heuristic procedures based on the demand matrix and the road network, integrated by “fixed supply” such as underground, urban railways, and those transit lines identified by Authority and located on the road network as fixed links with characteristics constant with flows; in the second and third phases the lines of main and feeder networks are designed respectively. In regard to this classification, the 2 phases are applied to define express lines initially, and subsequently main, in which express lines become “fixed supply” for following main lines design. This model has been applied to the Public Transit Network Design of the city of Rome, Italy.

A bus network design procedure with elastic demand for large urban areas

The paper deals with a procedure for solving the bus network design problem with elastic demand in a large urban area and its application in a real context (city of Rome). The solution procedure consists of a set of heuristics, which includes a first routine for route generation based on the flow concentration process and a genetic algorithm for finding a sub-optimal set of routes with the associated frequencies. The design criteria are addressed to develop an intensive rather than extensive bus network in order to improve efficiency, integration among direct routes and effective transfer points that strongly affect service quality and ridership. The performances of the transportation system are estimated on a multimodal network taking into account the elasticity of the demand. The final goal of the research is to develop a design framework aiming at shifting the modal split towards the public transport.

Heuristic methods for the optimal location of road traffic monitoring

The paper deals with two different heuristic approaches for solving the problem of optimal location of traffic count sections (OLTCS), which is a crucial issue of the design of area wide ITS traffic monitoring centers. The first method applies deterministic rules on O/D flows and O/D pairs coverage. The second is based on a genetic algorithm (GA). Both are applied on a real size extra-urban road network and compared to a state-of-the art rule widely used in practical applications

Traffic state estimation based on data fusion techniques

The capability to detect and/or forecast traffic conditions is of utmost importance in road management applications. Recent advances in technology have made available numerous new monitoring systems exploiting larger fleet of probe vehicles. Together with traditional volume and time mean speed measurements relative to a local section monitored continuously in time, probe vehicles provide additional type of data, such as space mean speed and travel time, relative to road segments monitored in specific time intervals. Therefore, the aim of this paper is to study how to exploit available information detected by new monitoring devices in the estimation of traffic flow conditions. Different types of data fusion techniques have been analyzed, namely measurement data fusion and state vector fusion, in several simulations carried out on a simple test network, traveled by probe vehicles and composed of 9 cells with an on ramp and an off ramp and with two fixed traffic sensors located in two different cells. Test results are promising and indicate higher accuracy of estimates obtained with new methods, particularly in the case of measurement data fusion.

Relationship between Parking Location and Traffic Flows in Urban Areas

In the last twenty years, most studies on parking demand distribution have been analyzing user-choice criteria, and after determining the utilization level of proposed parking facilities, they have identified the optimal pattern of the parking plan, based on the optimization of only two parameters: parking cost and walking distance. The most common method used to search for optimal allocation criteria, was a verification of different scenarios for parking demand satisfaction.

Walkability Indicators for Pedestrian-Friendly Design

This paper presents an analysis of walking indicators related to the structure of the road network, differentiated by measures of the quality, connectivity, and proximity of the road network. These measures were computed for various zones of the city of Rome and for the historical center of Lucca and Venice in Italy. The aims of the study were (a) to understand whether some measures were more suitable than others for describing the walkability (i.e., accessibility to walking) of an area, (b) to define the best single measure or the optimal combination of measures to describe the walkability of an area, (c) to define some benchmark values for the analyzed walkability measures, and (d) to obtain valuable guidelines to define a pedestrian-oriented road network. The results showed the importance of variables such as the number of nodes and the size of the blocks. Moreover, the results demonstrated that although single measures of connectivity were not self-explanatory for describing walkability, the combination of various measures could be more effective. Finally, the study derived the benchmark values of 3 to 6 nodes per hectare for the density of nodes, 0.5 to 0.9 hectare per block for the size of blocks, and 800 m for the maximum walking distance for a pedestrian-friendly, transit-oriented development.

A new method to recover the correct land use and public transport interaction

In the last years the increasing use of private vehicles in urban areas creates negative impacts on the society particularly for the congestion, implying an increase of travel times, of air and noise pollution, of accidents, and the excessive production of greenhouse gases and land consumption. Public transport could represent a more efficient mode of travel with respect to the car, playing an important role to provide a more sustainable transport system. However, infrastructural actions operated on the public transport system are usually of long term, with respect to actions operated on land use, thus creating a considerable temporal gap between the land use and the transport system development. Starting from these remarks, the present study proposes a new method to overcome this temporal discrepancy, using the residual capacity of the mass transit system (existing or its short term development) as a variable to indicate the location and the magnitude of new residential and activities developments. The method has been applied to the city of Rome (Italy), suggesting how the Local Authority could guide the development of the urban area in a sustainable way for the next years.

A dynamic mesoscopic emission model for signalized intersections

The paper develops a mesoscopic emission model for signalized intersections that takes into account the dynamic variability of traffic conditions. It starts from an analytical model based on Akcelic theory and it permits to distinguish between vehicles in queue and vehicles entering/exiting the queue (deceleration and acceleration phases) using data derived from a Dynamic Traffic Assignment (DTA).

A procedure for urban route travel time forecast based on advanced traffic data: Case study of Rome

In this paper, authors report a procedure to forecast the route travel time, based on different advanced traffic data, both historical and current.

The value of information for the accessibility to concurrent transit system services

The accessibility to different transport systems is an essential variable for modal choice, and not only for the choice between public and private transport, but also between concurrent transit systems. The study would like to identify and quantify the value of information (VOI) in the accessibility to concurrent transit services. In particular, the type of information considered and assessed is both en-route and pre-trip information provided to a user who has to choose between the concurrent transit services available. A methodology will be presented in order to identify and quantify the VOI, based on the development of behavioral models that make use of random utility theory. These models have been calibrated and validated using two different samples of data collected by a Revealed Preference (RP) survey to 200 users choosing between the different transit services available connecting Fiumicino Airport to the city center of Rome (Termini Station) in Italy. The proposed methodology is based on the development of behavioral models that make use of random utility theory. In particular two types of discrete choice models belonging to the family of random utility models are proposed: Multinomial Logit model (ML) and Nested Logit model (NL).