1,720,973 research outputs found
Comparative analysis of naval costs for accessibility to Sardinia and Corsica
No full textIn this study, the influence of naval transportation costs on the accessibility of Sardinia and
Corsica has been evaluated, making an analytical comparison between the effective costs
for the Tirrenia, Moby, SNCM, Corsica Ferries, and La Méridionale companies [hereinafter
Companies] to carry out a roundtrip journey (RT). The evaluation has been realized with an
analytical model of costs, with the purpose of emphasizing the deep discrepancy between
the" demand" and" supply" systems of Italian naval transpor
Assessing The Impact Of Led-Illuminated Crosswalks On Pedestrian Safety
No full textThis study focuses on the impact of LED-illuminated crosswalks on pedestrian safety. The speed profile of vehicles approaching the crosswalk was measured with a Telelaser instrument.
In order to test the efficacy of the LED-lighting system on pedestrian safety, the field measurements were performed in several urban road segments in the metropolitan area of Rome (Italy) both in LED-illuminated and non-illuminated conditions. Drivers' behavior while approaching the crosswalk was analyzed in different road sections: two-lane road with one-way traffic, four-lane road with two lane in each direction and no median barrier, and two-lane road with one lane in each direction and no median barrier.
The results have shown that an integrated LED-lighting system embedded in the pavement generates a significant speed-reducing effect on vehicles, improving pedestrian safety at unsignalized crosswalks. It was found that vehicles’ speed at crosswalk decreases on average by 19-32% in illuminated conditions
A preliminary study of the potential impact of autonomous vehicles on residential location in Rome
No full textFully Autonomous Vehicles (AVs) can self-drive in all situations, offering the highest comfort to drivers, who can pursue several activities during their trips. Under this assumption, AVs will probably affect the perception of time and its value. The research presented in this paper is a first attempt to understand if the introduction of fully AVs may generate residential relocation from the city center to the suburbs due to a different time perception. Using Stated Preferences (SP) survey technique, discrete choice modelling, and traffic simulation, the effect of urban sprawl of AV-cities on the road network in terms of congestion was evaluated. The relocated demand, estimated thorough ad hoc calibrated behavioral models, was assigned to the road network of the city of Rome (Italy). Results show an increase in travel times (about 12%) for suburban residents commuting to work in city center due to the extra-demand relocated. Instead, intra-urban road congestion would benefit from lower traffic volumes (about −10% in travel times). Moreover, this work shows the positive impact of the ride-sharing schemes with AVs by simulating different penetration rates. These results, however, should be taken with caution, as the sample is very small, travel time and travel monetary costs are ignored, as are housing costs, and mode choice and residential location are not modelled simultaneously
Integrated approach for the road traffic greenhouse gas emissions calculation in a life-cycle perspective
No full textThis research aims at defining a model to assess the Greenhouse Gases emissions of an entire vehicle fleet, from a life cycle perspective, based on the results of specific traffic simulations. The environmental performance of the City of Rome private transport network was evaluated in terms of carbon dioxide equivalent (CO2 eq), was based on the life cycle impacts of the different vehicle categories in circulation and based on the vehicle flow on the road net-work. In terms of life-cycle environmental impact, fully electric vehicles were found to be those with the highest emission values as regards construction, maintenance, and dis-posal, both compared to internal combustion vehicles and hybrid vehicles. Nevertheless, a 100% penetration of electric vehicles in the circulating fleet can potentially generate a reduction of GHG of the order of 39% at transport network level
A cost evaluation analysis for naval accessibility to Sardinia and Corsica
No full textAn analytical model for the evaluation of the naval transportation costs in Ro-Pax
services is presented in order to compare the naval accessibility of two main Mediterranean
islands with their mainland countries
An innovative car sharing electric vehicle system: An Italian experience
No full textThis paper focuses on the introduction of an innovative electric vehicle car sharing system in Rome. Specifically, the system is designed for a university community (Roma Tre University), thus it is reserved for students and employees. The fleet is composed by 30 electric vehicles and 56 recharging points have been installed in several departments of the University. The service is designed as a free floating system, allowing commuting and leisure trips. The trips are not spatially limited, but the rental has to be opened and closed within a delimited area in the city. This paper analyses the starting stage of the project. The results of a RP (Revealed Preferences) and SP (Stated Preferences) survey are discussed. The survey has been filled out by a sample of 950 potential users. Important indications have been obtained on the behavioural attributes that mostly affect the electric vehicle car sharing subscriptors and service utilization. Afterwards, specific behavioural models based on random utility theory have been proposed for predicting modal switch, considering the introduction of the new service. Attributes such as the âGreen Attitudeâ, the âSharing Attitudeâ and the âDevice attitudeâ have been analysed in terms of their impacts on the mode choice, underlining their weight and statistical significance compared to attributes as distances and travel times
Transit network design for small-medium size cities
No full textThis paper proposes a novel heuristic to solve the network design problem for public transport in small-medium size cities. Such cities can be defined as those with a diameter of a few kilometers with up to a few hundred thousand residents. These urban centers present a specific spatial configuration affecting the land use and mobility system. Transportation demand is widespread in origin and concentrated in a small number of attraction points close to each other. This particular structure of demand ('many-to-few') suggests the need for specific methodologies for the design of a transit system at a network level. In this paper, such design methodologies are defined in terms of models and solution procedures and tested on a selected case study. The solution methods show promising results. The key variables of the model are the routes and their frequencies. The constraints of the problem affect the overall demand to be served, the quality of the proposed service (transfer, load factors) and the definition of routes
Fit for 2030? Possible scenarios of road transport demand, energy consumption and greenhouse gas emissions for Italy
No full textDecarbonizing the transportation sector is one of the key challenges to reduce greenhouse gas (GHG) emissions and meet EU Green Deal 2030 targets. Road transport decarbonization requires a holistic approach encompassing various strategies and interventions aimed at fostering the sustainable transition of this sector. This challenge is crucial given that road is responsible for over 90% of the overall transport GHG emissions.
Within this framework, this study aims, for the Italian case, to: a) estimate the national passenger and freight road travel demand with respect to three different time periods: 2005 (reference year for EU “fit for 55” target); 2019 (last consolidated pre-covid year); 2022 (base-line year); b) define possible road transport scenarios to 2030 following the Avoid-Shift-Improve (ASI) approach; c) estimate the GHG and energy consumption inventory related to national road transport for the 2005, 2019; 2022 and 2030 scenarios. Due to the current “deep uncertainty” regarding key economic and social variables in this period, two forecasting scenarios – named “moderate decarbo” and “high decarbo” – were designed and based on different and somewhat opposite hypotheses on exogenous variables (e.g., GDP) and penetration rates of measures and policies promoting sustainable transportation (e.g., subsidies for electric vehicles) already in place. Although the current European legislation refers only to Tank-to-Wheel (TtW) objectives, this study included also the Well-to-Wheel (WtW) evaluation, which is more accurate in assessing the GHG impact of different policies, energy carriers, and technologies. As for the past, results suggest that GHG reductions over the period 2005-2022 are mostly due to crises and stagnation of the Italian economy. “Moderate decarbo” forecasts for 2030 lead to a 12% reduction of TtW (and 15% for WtW) GHG emissions compared to 2005 levels, with ASI policies compensating for the assumed economic growth. In any case these values are far from the EU “Fit for 55” goal setting a 43.7% reduction of TtW emissions. Even under very favourable hypotheses (“high decarbo” scenario), GHG emissions might be reduced by only 28% for TtW and 33% for WtW, still well below EU objectives. Furthermore, passengers and freight show very different behaviour, with the latter contributing to emissions more than proportionally, and “shift-to-rail” policies, although very useful in some market segments, contribute moderately at the overall national level. The main conclusion of this study is that the pathway towards road transport decarbonization in Italy (and possibly in other EU Countries) is very uncertain, and the ambitious 2030 target is unlikely to be met with currently planned policies alone. The transportation system needs to be constantly monitored, and new policies have to be implemented to reach higher emissions reduction goals
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