Agostino Nuzzolo

An adaptive freeway traffic state estimator

Real-data testing results of a real-time nonlinear freeway traffic state estimator are presented with a particular focus on its adaptive features. The pursued general approach to the real-time adaptive estimation of complete traffic state in freeway stretches or networks is based on stochastic nonlinear macroscopic traffic flow modeling and extended Kalman filtering. One major innovative aspect of the estimator is the real-time joint estimation of traffic flow variables (flows, mean speeds, and densities) and some important model parameters (free speed, critical density, and capacity), which leads to four significant features of the traffic state estimator: (i) avoidance of prior model calibration; (ii) automatic adaptation to changing external conditions (e.g. weather and lighting conditions, traffic composition, control measures); (iii) enabling of incident alarms; (iv) enabling of detector fault alarms. The purpose of the reported real-data testing is, first, to demonstrate feature (i) by investigating some basic properties of the estimator and, second, to explore some adaptive capabilities of the estimator that enable features (ii)-(iv). The achieved testing results are quite satisfactory and promising for further work and field applications.

A BEHAVIOURAL CHOICE MODEL FOR THE EVALUATION OF RAILWAY SUPPLY AND PRICING POLICIES

This paper presents a choice model that can be used to simulate the impacts of variations in medium-long distance railway service characteristics (e.g. timetable, travel time, prices) on user choice of service type, run and class. The model, based on a nested-logit service/run/class/access-egress mode choice model, explicitly takes into account the desired departure (arrival) time and related early/late schedule delay penalties.

Urban Freight Policy Innovation for Rome’s LTZ: A Stakeholder Perspective

City distribution plays a key role in supporting urban lifestyles, helping to serve and retain industrial and trading activities, and contributing to the competitiveness of regional industry. Despite these positive effects, it also generates negative (economic, environmental and social) impacts on cities worldwide. Relatively little attention has been paid to these issues by researchers and policymakers until recently. The analyses found in City Distribution and Urban Freight Transport aim to improve knowledge in this important area by recognizing and evaluating the problems, with a focus on urban freight transport systems.

Real-Time Freeway Network Traffic Surveillance: Large-Scale Field-Testing Results in Southern Italy

This paper reports on some large-scale field-testing results of a real-time freeway network traffic surveillance tool that has recently been developed to enable a number of real-time traffic surveillance tasks. This paper first introduces the related network traffic flow model and the approaches employed to traffic state estimation, traffic state prediction, and incident alarm. The field testing of the tool for these surveillance tasks in the A3 freeway of 100 km between Naples and Salerno in southern Italy is then reported in some detail. The results obtained are quite satisfactory and promising for further future implementations of the tool.

Urban freight transport and city logistics policies: Indications from Rome, Barcelona, and Santander

ABSTRACT This article compares the characteristics of urban freight transport in Rome, Barcelona, and Santander and the logistics measures being implemented in the three cities. The analysis is based on three similar surveys carried out in recent years involving interviews with retailers and transport operators. The main objective of this study is to evaluate the similarities and differences in terms of spatial patterns, current regulations, socioeconomic characteristics, commercial structures, freight demand characteristics, and current distribution patterns followed by different transport and logistics operators. The study shows that there are some different patterns of urban distribution that need to be taken into account when implementing city logistics measures in order to meet desired sustainability goals.

The Schedule-Based Approach in Dynamic Transit Modelling: A General Overview

Recently, beside the traditional frequency-based approach in dynamic modelling of transit networks, a new approach, called schedule-based, has been developed. This approach refers to services in terms of runs, using the arrival/departure times at stops of each vehicle, and allows us to take into account the time evolution of both supply and demand, as well as to obtain the load of each vehicle at each stop. This modelling approach requires a more precise specification of user behaviour mechanism and a specific treatment for origin/destination matrices, supply models, path choice and assignment models. In this paper the state-of-the-art of each of these points, with a classification of existing models and the future perspectives of the research in this field, is provided.

Advanced public transport and intelligent transport systems: new modelling challenges

ABSTRACT Transit system ‘big data’ collecting and processing, and bidirectional communication between transit travellers and information centres are emerging as two factors that enhance the tools supporting short-term forecasting of network status for transit operations control and for traveller information. However, the current methodologies applied in these tools do not seem to have reached the level of research in the field of transit network modelling. Therefore, several methodological issues connected to the development of such tools are analysed in this paper. These issues concern application and development of real-time on-board load short-term forecasting methods, real-time best path advice, real-time transit assignment modelling, individual path choice modelling, and real-time updating and upgrading of demand and supply model parameters.

Urban freight transport policies in Rome: lessons learned and the road ahead

Given that few studies have investigated the effects of implementing city logistics measures, this paper focuses on actions implemented in the inner area of Rome in the last 10 years in order to improve both livability and freight distribution, providing insights into the effectiveness of such measures. The analysis covers the famous inner area of the city where the main tourist monuments are located and includes several pedestrianized shopping streets. Evaluation is based on data collected in 1999 and 2008 consisting of traffic counts and interviews with retailers and truck drivers. The implemented measures provided effective in abating through-traffic, in reducing the share of transport on own-account and in increasing the use of less polluting vehicles. Further, the increase in the number of stops per tour, in the average quantity delivered and hence in the average loading factor was revealed. Although all these changes improved the freight transport within the city, some critical issues remain and further measures have to be implemented.

Tactical and Operational City Logistics: Freight Vehicle Flow Modelling

This paper first classifies city logistics measures that city administrators can use to reduce the negative impacts of urban freight transport, in relation to planning (i.e. strategic and tactical/operational). The focus then shifts onto models developed to support the assessment of tactical and operational measures. The assessment procedures require the simulation of freight transport demand and hence the estimation of freight vehicle origin-destination (O-D) flows. These O-D flows can be obtained from the simulation of delivery tours. Therefore, the paper presents a system of models able to simulate delivery tours using an aggregate approach. Such models allow us to capture actors’ choices which can be influenced by tactical and operational measures. They were calibrated and tested using the surveys carried out in the inner area of Rome, where more than 500 truck drivers were interviewed. Some results of the validation of the models are also presented.

City logistics long-term planning: simulation of shopping mobility and goods restocking and related support systems

The growing necessity to improve city sustainability and liveability has pushed local administrators to look also at medium/long-term city logistics measures, such as land-use governance policies. In order to assess long-term scenarios, it is necessary to have models and methods able to take into account the effects on shopping mobility and goods restocking, generated by these classes of measures (e.g. relocation of shopping zones). Besides, we have to consider that modifications of shopping attitudes, deriving from changes of demographic and socio-economic characteristics of end consumers, can impact on purchasing behaviour and hence on restocking mobility. This paper discusses a number of issues related to the simulation of medium/long-term scenarios and presents a system of models that consider shopping mobility and restocking jointly. The presented shopping demand models, in combination with urban restocking models, are implemented within a simulation support system named City Logistics Analysis and Simulation Support System and are used to assess the effects on the freight restocking due to demographic and socio-economic variations including some hypotheses on new land-use development governance measures in a medium-size urban area. The main results confirm the modelling goodness and, at the same time, demonstrate that changes in demographic and socio-economic characteristics could cause relevant effects, in particular increasing car use in shopping mobility. The growing e-shopping could limit the negative effects of these changes, but the impacts of home deliveries have to be considered. The relocation of commercial and logistics centres, closer to the residential distribution, could drive a different restocking pattern with a consequent reduction in freight vehicle mobility. Anyway, this reduction is not very relevant and therefore further city logistics measures have to be implemented.