Traffic congestion: the problem and how to tackle it

As the culmination of a project financed by the Technical Cooperation Agency of the Federal Republic of Germany (GTZ), ECLAC has just published Congestión de tránsito - El problema y cómo enfrentarlo, Cuadernos de la Cepal series, No. 87. The text of 194 pages analyses the negative impacts of congestion and the multidisciplinary efforts that are needed to keep it under control, through the design of appropriate policies and measures. Congestion control is part of the development of a strategic vision of how a city should develop which can make it possible to harmonize the needs of mobility, growth and competitiveness, which are so necessary today and in the future, with the sustainability of cities and the improvement of their quality of life.The task is complex and it is not easy to find appropriate solutions. The present publication presents tools for tackling this crucial problem. Everything indicates that it calls for high professional and leadership qualities on the part of the authorities, and that it must have the active support of the citizens.This edition of the Bulletin presents a summary of the main conclusions of the publication and it is stressed that ECLAC can conduct local workshops to analyze the problem and how to tackle it.

ECLAC contributes with new workshops towards the goal of easing traffic congestion

A number of cities in Latin America played host to workshops on measures for reducing traffic congestion, as part of efforts to publicize the results of a project recently completed by ECLAC, and which received support from the German Agency for Technical Cooperation (GTZ). Congestion is beginning to pose a threat to the quality of life of the cities of the region; the most obvious manifestation of this congestion is the increase in daily travel time, especially in peak hours.The workshops are a contribution to efforts to curb congestion, since they help foster awareness of the extent of the negative consequences generated by the phenomenon, and are a means of publicizing options for dealing with it. This edition of the Bulletin outlines the contents of the workshops and their results. The workshops are offered to urban authorities and other institutions interested in training staff employed in positions involving traffic management.

Traffic congestion: its economic and social consequences

Urban transport in the largest Latin American and Caribbean cities consumes about 3.5% of regional GDP — a percentage that is inflated by the effects of traffic congestion. In addition to the costs of congestion in terms of lost economic efficiency, there are also negative consequences in terms of social cohesion. The phenomenon of traffic congestion, which is caused mainly by relatively wealthy car drivers, lengthens journey times and, more importantly, forces up public transport fares. Owning a car is one of the fruits of human progress; using it in conditions of acute congestion or contamination is a social ill.

Chile: Port congestion and efficient rationing in cargo transfer operations

Includes bibliography.

Traffic congestion: the problem and how to deal with it

The text of 194 pages analyses the negative impacts of congestion and the multidisciplinary efforts that are needed to keep it under control, through the design of appropriate policies and measures. Congestion control is part of the development of a strategic vision of how a city should develop which can make it possible to harmonize the needs of mobility, growth and competitiveness, which are so necessary today and in the future, with the sustainability of cities and the improvement of their quality of life.The task is complex and it is not easy to find appropriate solutions. The present publication presents tools for tackling this crucial problem. Everything indicates that it calls for high professional and leadership qualities on the part of the authorities, and that it must have the active support of the citizens.This edition of the Bulletin presents a summary of the main conclusions of the publication and it is stressed that ECLAC can conduct local workshops to analyze the problem and how to tackle it.

Congestion Effects on Regional & System Emission and Consumers Allocated Cost

This paper considers the congestion effects on emission and consumers' allocated cost. In order to consider some environmental and operational effects of congestion, an environmental constrained active-reactive optimal power flow (AROPF) considering capability curve is presented. On outage conditions, the total cost of the system will increase. On the other hand in power systems, the operating cost and system emission have conflicted objectives, then it may be concluded that the outage in the system may lead to a total emission decrease. In this paper the famous Aumann-Shapley method is used as a pricing methodology. Two case studies such as 14-bus and US-bus IEEE test systems are conducted. Results demonstrate that, although the line outage in power systems leads to increase the total cost, the amount of emission depending on the place where the outage occurs can be more than, less than or equal to the normal conditions' emission. Also results show that although from power sellers' standpoint the well-known Aumann-Shapley method is a precise pricing method to cover the incurred cost with an acceptable error that can show the real effect of congestion on consumers' cost, from consumers' standpoint it is not a good method for cost allocation, because some consumers will face with an increase in cost and the others will face with a decrease on their cost.

Splenic congestion associated with acepromazine administration in dogs

The effects splenic dilatation induced by acepromazine in a prospective, randomized study. Thirtythree adult mongrel dogs were divided into two groups designated as AG (acepromazine 0.05 mg/kg, i.v., n = 23) and CG (0.9% sodium chloride administered at a similar volume, n = 10). In both groups underwent sonographic examinations before (T0) and fifteen minutes (T15) after drug injection. The thickness spleen and splenic vein width were measured. Higher thickness was found in the AG group at T15 (2.47 cm) when compared to that at T0 (2.06 cm, p = 0.016), while the T0 (2.33 cm) and T15 (2.39 cm) measures did not differ within the CG group. Moreover, the splenic vein width was higher (p = 0.013) at T15 than at T0 in the AG group. Based on results of this study, we concluded that acepromazine, in doses of 0.05 mg/kg, promotes splenomegaly in dogs after fifteen minutes of the injection.

SLBN: A Scalable Max-min Fair Algorithm for Rate-Based Explicit Congestion Control

The growth of the Internet has increased the need for scalable congestion control mechanisms in high speed networks. In this context, we propose a rate-based explicit congestion control mechanism with which the sources are provided with the rate at which they can transmit. These rates are computed with a distributed max-min fair algorithm, SLBN. The novelty of SLBN is that it combines two interesting features not simultaneously present in existing proposals: scalability and fast convergence to the max-min fair rates, even under high session churn. SLBN is scalable because routers only maintain a constant amount of state information (only three integer variables per link) and only incur a constant amount of computation per protocol packet, independently of the number of sessions that cross the router. Additionally, SLBN does not require processing any data packet, and it converges independently of sessions' RTT. Finally, by design, the protocol is conservative when assigning rates, even in the presence of high churn, which helps preventing link overshoots in transient periods. We claim that, with all these features, our mechanism is a good candidate to be used in real deployments.

Integration of congestion pricing and intertemporal preference rate in social welfare function

Assessing social benefits in transport policy implementation has been studied by many researchers using theoretical or empirical measures. However, few of them measure social benefit using different discount rates including the inter-temporal preferences rate of users, the private investment discount rate and the inter-temporal preferences rate of the government. In general, the social discount rate used is the same for all social actors. Therefore, this paper aims to assess a new method by integrating different types of discount rate belonging to different social actors in order to measure the real benefits of each actor in the short, medium and long term. A dynamic simulation is provided by a strategic Land-Use and Transport Interaction (LUTI) model. The method is tested by optimizing a cordon toll scheme in Madrid considering socio- economic efficiency and environmental criteria. Based on the modified social welfare function (WF), the effects on the measure of social benefits are estimated and compared with the classical WF results as well. The results of this research could be a key issue to understanding the relationship between transport system policies and social actors' benefits distribution in a metropolitan context. The results show that the use of more suitable discount rates for each social actor had an effect on the selection and definition of optimal strategy of congestion pricing. The usefulness of the measure of congestion toll declines more quickly overtime.

Integration of congestion pricing and intertemporal preferences rate integration in social welfare function

Many researchers have used theoretical or empirical measures to assess social benefits in transport policy implementation. However, few have measured social benefits by using discount rates, including the intertemporal preference rate of users, the private investment discount rate, and the intertemporal preference rate of the government. In general, the social discount rate used is the same for all social actors. This paper aims to assess a new method by integrating different types of discount rates belonging to different social actors to measure the real benefits of each actor in the short term, medium term, and long term. A dynamic simulation is provided by a strategic land use and transport interaction model. The method was tested by optimizing a cordon toll scheme in Madrid, Spain. Socioeconomic efficiency and environmental criteria were considered. On the basis of the modified social welfare function, the effects on the measure of social benefits were estimated and compared with the classical welfare function measures. The results show that the use of more suitable discount rates for each social actor had an effect on the selection and definition of optimal strategy of congestion pricing. The usefulness of the measure of congestion toll declines more quickly over time. This result could be the key to understanding the relationship between transport system policies and the distribution of social actors? benefits in a metropolitan context.

A model for setting services on auxiliary bus lines under congestion

In this paper, a mathematical programming model and a heuristically derived solution is described to assist with the efficient planning of services for a set of auxiliary bus lines (a bus-bridging system) during disruptions of metro and rapid transit lines. The model can be considered static and takes into account the average flows of passengers over a given period of time (i.e., the peak morning traffic hour) Auxiliary bus services must accommodate very high demand levels, and the model presented is able to take into account the operation of a bus-bridging system under congested conditions. A general analysis of the congestion in public transportation lines is presented, and the results are applied to the design of a bus-bridging system. A nonlinear integer mathematical programming model and a suitable approximation of this model are then formulated. This approximated model can be solved by a heuristic procedure that has been shown to be computationally viable. The output of the model is as follows: (a) the number of bus units to assign to each of the candidate lines of the bus-bridging system; (b) the routes to be followed by users passengers of each of the origin–destination pairs; (c) the operational conditions of the components of the bus-bridging system, including the passenger load of each of the line segments, the degree of saturation of the bus stops relative to their bus input flows, the bus service times at bus stops and the passenger waiting times at bus stops. The model is able to take into account bounds with regard to the maximum number of passengers waiting at bus stops and the space available at bus stops for the queueing of bus units. This paper demonstrates the applicability of the model with two realistic test cases: a railway corridor in Madrid and a metro line in Barcelona Planificación de los servicios de lineas auxiliares de autobuses durante las incidencias de las redes de metro y cercanías. El modelo estudia el problema bajo condiciones de alta demanda y condiciones de congestión. El modelo no lineal resultante es resuelto mediante heurísticas que demuestran su utilidad. Se demuestran los resultados en dos corredores de las ciudades de Barcelona y Madrid.

Papers presented at the congestion pricing symposium.

Mode of access: Internet.

Trends in urban roadway congestion: 1982 to 1991. Volume 1: annual report.

Texas Department of Transportation, Austin

Trends in urban roadway congestion: 1982 to 1991. Volume 2: methodology and urbanized area data.

Texas Department of Transportation, Austin

Technologies that enable congestion pricing : a primer.

"October 2008."