Search results for "Urban transportation"

A general model for predicting the environmental impact of urban transportation

2002

In this paper a generalised model is described for the analysis of the pollutant substances released in the atmosphere by urban transportation means. It essentially requires data referring to the running transportation fleet, year by year, that are generally on disposal of the local administrators through official data-bases. Pollutant emissions are here taken into account by means of the algorithms provided by the COPERT methodology, that applies to many European countries. The method, by means of a suitable statistical analysis of data concerning the running car fleet, allows also the definition of an useful indicator, that is the “yearly average vehicle”, that can be assumed as represent…

Tramways Revisited: An analysis of the role of tramways in urban transportation during the twentieth century

2007

The structure and evolution of tramway and metro networks are studied in this article using two models involving addition/accretion and expansion/diffusion modes of growth, respectively. Data for t...

An Object-Oriented Approach to Discrete-Event Simulation Applied to Underground Railway Systems

1999

This paper describes the implementation of an object-oriented simulator that supports the determination of timetables and the design of on-line control policies for underground rail way systems. The simulator has been developed on the basis of a new approach to object- oriented modelling. Such an approach has been used to design a development tool that supports the generation of simulation codes and is able to automatically define the skeleton of a code.

Sleep and sleepiness in shift-working tram drivers

2020

Driver sleepiness contributes to traffic accidents. However, sleepiness in urban public transport remains an understudied subject. To fill this gap, we examined the sleepiness, sleep, and on-duty sleepiness countermeasures (SCMs) in 23 tram drivers working morning, day, and evening shifts for three weeks. Sleepiness was measured using Karolinska Sleepiness Scale (KSS). Nocturnal total sleep time (TST) was measured with wrist actigraphy. SCMs and naps were self-reported with a smartphone application. Caffeine and napping were considered effective SCMs. Severe sleepiness (KSS >= 7) was observed in 22% of shifts with no differences between shift types. Rest breaks were associated with slight r…

An integrated environmental indicator for urban transportation systems: description and application

2015

A simplified version of the ecological footprint method is proposed for assessing the environmental performances of urban transportation systems. The method, starting from the knowledge of the composition of the running vehicular fleet, is here applied to a southern Italian province. It represents a synthetic indicator of the environmental pressure exerted by the system also matching the pollutant emissions with the carrying capacity of the site. Particularly, the forested area needed to absorb the CO2 emissions of the system is compared with the total forested area of the province. The results of the case-study indicates the yearly maximum distance that each vehicle of the fleet can cover …

Assessing the Ecological Footprint of an Urban Transportation System

2003

The ecological footprint methodology is here applied to the urban transport system of the Italian town of Palermo (Sicily). By only using the current running fleet, a synthetic indicator represented by the "equivalent bio-productive" land, corresponding to the actual transport configuration, will be built up. This indicator can be usefully adopted for ranking various options in the urban context referring, for example, to different arrangements of the transportation demand between private and public means. This could allow local administrations to environmentally hierarchizing alternative plans concerning the urban transportation

URBAN TRANSPORTATION GOVERNANCE AND WICKED PROBLEMS: A SYSTEMIC AND PERFORMANCE ORIENTED APPROACH

At an urban level, among the services that the public sector is called upon to provide, transportation plays a central role (Meyer & Miller, 2000). Urban mobility systems are complex. This complexity – characterized by pluralism, institutional fragmentation and uncertainty – determines what literature defines as ‘wicked’ problems (Rittel & Webber, 1973); namely issues that are hard to define and manage, and often lead to counterintuitive behaviours when actions are taken to resolve them. In the last 40 years, Public Administrations around the world experienced various reform processes. These processes - that were aimed at overcoming the limitations of the institutional settings already in p…

Applying a new synthetic environmental indicator to urban transportation scenario

2002

Through this work will be presented a suitably modified version of a simple model devoted to the evaluation of pollutant matters released in urban contexts by the transportation sector. The method, essentially referring to the pollutant emission factors provided within the European "COPERT III" approach, only requires the knowledge of data concerning the running car fleet on the analysed site. The methodology is here utilised for comparing environmental and energy effects of different transportation policies to be adopted in a given urban area. By imposing modal changes to the transportation demand and, consequently, by re-allocating people from cars to public means, the effects on the rele…

Solving congestion in cities : policies and contradictions

2009

International audience; Most cities in the world are now facing traffic gridlock. Local governements and transportation authorities are trying to tame a phenomenon which takes in fact very different forms depending on the level of social and economic development. Is it really possible to compare freeway gridlock in Los Angeles with rickshaw gridlock in Dhaka, Bangladesh ? When French cities embrace the development of urban bicycling, Chinese cities limit the use of bicycles. Using cases of cities in different parts of world, this presentation willl try to find some common trends in urban mobility policies and examine some contradictory developments.

Estimating pollutant emissions based on speed profiles at urban roundabouts: A pilot study

2019

The paper describes the pilot study conducted to assess the feasibility of the empirical approach utilizing vehicle trajectory data from a smartphone app and the Vehicle-Specific Power methodology to estimate pollutant emissions at urban roundabouts. The goal of this research phase is to acquire instantaneous speed data from a sample of six roundabouts located in the road network of the City of Palermo, Italy, and quantify emissions generated by the test vehicle through the examined roundabouts. For the case studies of roundabouts acceleration events in the circulating and exiting areas contributed to about 25% of the emissions for a given speed profile. More in general, the results from th…