2,919 research outputs found
LUTI models, freight transport and freight facility location
The subject of this book is the new scientific research in the field of modelling the interaction between land use and transport (LUTI modelling). Transport and the location of activities in space have been important themes of study in engineering, social sciences and urban and regional plannin
Simulating the Effects of Shopping Attitudes on Urban Goods Distribution
Studies of urban freight mobility traditionally focused only on restocking flows and usually neglected the linkage with shopping activities even if end consumer's choices in relation to the type of retail undoubtedly impact on freight distribution flows. The paper focuses on the distribution of urban freight facilities, the choices of type of retail and the travel mode used and some models for simulating the choice of retail outlet and the transport mode are presented. The models, jointly with urban freight demand models were used to assess the effects of some land-use scenarios and to define optimal spatial distribution of urban freight facilities able to improve city sustainability and to meet the interests of end consumers, freight operators and society. The results of an application of this method to a test site are also reported and discussed
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
Dynamic optimal travel strategies in intelligent stochastic transit networks
This paper addresses the search for a run-based dynamic optimal travel strategy, to be supplied through mobile devices (apps) to travelers on a stochastic multiservice transit network, which includes a system forecasting of bus travel times and bus arrival times at stops. The run-based optimal strategy is obtained as a heuristic solution to a Markovian decision problem. The hallmarks of this paper are the proposals to use only traveler state spaces and estimates of dispersion of forecast bus arrival times at stops in order to determine transition probabilities. The first part of the paper analyses some existing line-based and run-based optimal strategy search methods. In the second part, some aspects of dynamic transition probability computation in intelligent transit systems are presented, and a new method for dynamic run-based optimal strategy search is proposed and applied
Urban Freight Transport Measures: Environmental Evidences from the Cities
The rapid freight transportation increasing in urban and metropolitan areas contributes to congestion, air pollution, noise and to raise logistic costs, and hence the price of products. In addition, a combination of different types of vehicles on the road increases the risk of accidents. Moreover, the new policies of freight distribution provide daily deliveries. A so far distribution of goods has not been in accordance with people wishes regarding the city\'s space and environment. Sustainable city logistics solutions have to be implemented in order to riduce the effects of freight transport without penalising the life of the city. For example, as it happens in passenger mobility we can brave the problems related to externalities related to transport addressing to transit. It allows us to do not reduce accessibility and penalise the life of the city. At the same way, city logistics has to investigate the possible solutions that allow us to reduce externalities, to increase sustainability without damaging the city life. Around the world, different types of city logistics measures have been proposed and implemented, but sometimes they have not given the expected results. Thus, as it happens in the analysis of passenger mobility, in which we have different classes of measures that can be implemented in relation to city structure and level of demand, the same should be desired for freight mobility. In this context, the paper, within the field of city logistics sustainability, recalls the overview of measures to be implemented, in a "what if" framework, with strong references to the ex-post assessment carried out in order to support the definition of city logistics scenarios that should have to be evaluated ex-ante by simulation models. The analysis is done in relation to the goals of environemntal sustainability to be pursued and the main characteristics of analysed cities (e.g. population, density). In other words, the study presents the empirical relations among outcomes (e.g. reduction of greenhouse – CO2 - or air pollutant emissions – CO, NOx, SOx, PM) and city logistics measures. Both qualitative and quantitative trends of expected results related to environmental sustainability in function of city characteristics will be deepened. From this type of analysis, it will be possible to identify the maximum expected reduction of externalities obtainable from a given city logistics measure in relation to a specific cit
A Note on Riemann-Liouville Fractional Sobolev Spaces
Taking inspiration from a recent paper by Bergounioux et al., we study the Riemann-Liouville fractional Sobolev space W-RL,a+(s,p), for I = (a, b) for some a, b is an element of R, a < b, s is an element of (0,1) and p is an element of [1, infinity]; that is, the space of functions u is an element of L-P(I) such that the left Riemann-Liouville (1 - s)-fractional integral I-a+(1-s)[u] belongs to W-1,W-p (I). We prove that the space of functions of bounded variation BV(I) and the fractional Sobolev space W-s,W-1 (I) continuously embed into W-s,(1)(RL,a+) (I). In addition, we define the space of functions with left Riemann-Liouville s-fractional bounded variation, BVRL,a+s (I), as the set of functions u is an element of L-1(I) such that I-a+(1-s)[u] is an element of BV (I), and we analyze some fine properties of these functions. Finally, we prove some fractional Sobolev-type embedding results and we analyze the case of higher order Riemann-Liouville fractional derivatives
Understanding taxi travel demand patterns through Floating Car Data
This paper analyses the current structure of taxi service use in Rome, processing taxi Floating Car Data (FCD). The methodology used to pass from the original data to data useful for the demand analyses is described. Further, the patterns of within-day and day-to-day service demand are reported, considering the origin, the destination and other characteristics of the trips (e.g. travel time). The analyses reported in the paper can help the definition of space-temporal characteristics of future Shared Autonomous Electrical Vehicles (SAEVs) demand in mobility scenarios
Facilitating culturally diverse groups with visual templates in collaborative systems : increasing structuration to improve precision
Private car O-D flow estimation based on automated vehicle monitoring data: theoretical issues and empirical evidence
Data on the daily activity of private cars form the basis of many studies in the field of transportation engineering. In the past, in order to obtain such data, a large number of collection techniques based on travel diaries and driver interviews were used. Telematics applied to vehicles and to a broad range of economic activities has opened up new opportunities for transportation engineers, allowing a significant increase in the volume and detail level of data collected. One of the options for obtaining information on the daily activity of private cars now consists of processing data from automated vehicle monitoring (AVM). Therefore, in this context, and in order to explore the opportunity offered by telematics, this paper presents a methodology for obtaining origin–destination flows through basic info extracted from AVM/floating car data (FCD). Then, the benefits of such a procedure are evaluated through its implementation in a real test case, i.e., the Veneto region in northern Italy where full-day AVM/FCD data were available with about 30,000 vehicles surveyed and more than 388,000 trips identified. Then, the goodness of the proposed methodology for O-D flow estimation is validated through assignment to the road network and comparison with traffic count data. Taking into account aspects of vehicle-sampling observations, this paper also points out issues related to sample representativeness, both in terms of daily activities and spatial coverage. A preliminary descriptive analysis of the O-D flows was carried out, and the analysis of the revealed trip patterns is presented
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