Theoretical Approach to Predicting Traffic Queues at Short-Term Work Zones on High-Volume Roadways in Urban Areas

2003 ◽  
Vol 1824 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Gerald L. Ullman ◽  
Conrad L. Dudek
Keyword(s):  
Theoretical Approach ◽  
Urban Areas ◽  
High Volume ◽  
Work Zone ◽  
Primary Data ◽  
Short Term ◽  
Rational Representation ◽  
Traffic Volumes ◽  
New Perspective ◽  
Road Work

A new theoretical approach is described that more accurately predicts the length of queues that will develop when one or more lanes are closed for short-term freeway road work in an urban area. A model was developed that represents the interactions between diversion and traffic queuing on the freeway. The model is based on macroscopic fluid-flow analogies of traffic and a new perspective of the freeway corridor as a section of permeable pipe. Historical traffic volumes on the roadway serve as the primary data input into the model. Unlike other work zone analysis methods, the model presents a rational representation of how traffic queues stabilize upstream of temporary work zone bottlenecks in urban areas. The model can be calibrated to reasonably represent the magnitude of traffic queues developing upstream of actual work zone lane closures on urban freeways in Texas.

Queuing and Natural Diversion at Short-Term Freeway Work Zone Lane Closures

1996 ◽  
Vol 1529 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Gerald L. Ullman
Keyword(s):  
High Volume ◽  
Field Studies ◽  
Operating Conditions ◽  
Work Zone ◽  
Temporary Work ◽  
Short Term ◽  
Traffic Conditions ◽  
Traffic Stream ◽  
Traffic Volumes ◽  
Lane Closures

Research conducted to explore the effects of natural diversion on traffic conditions and travel patterns upstream of temporary work zone lane closures on high-volume urban freeways in Texas is described. Specific objectives were to explore how natural diversion affects traffic volumes at the exit and entrance ramps upstream of the lane closures and the interrelationships between the freeway and frontage road operating conditions that develop at a closure and the amount of natural diversion that occurs. The field studies showed that the rate of queue growth upstream of the short-term lane closures diminished significantly after the first hour at each site. Eventually, the queues approached a balanced state in which the upstream end of the queue became almost stationary. This stabilization was due to significant reductions in entrance ramp volumes both upstream of the freeway queue and within the limits of queuing, as well as to changes in exit ramp volumes within the queue. As a result of these ramp volume changes the constrained flow rate within the queue increased as a function of the distance upstream of the actual lane closure. Using the theory of shock waves in a traffic stream it was shown that the changes in ramp volumes and resulting impact on constrained freeway flow rates within the queue were consistent with the queue stabilization process observed at each site.

scholarly journals Forecasting Spatially-Distributed Urban Traffic Volumes via Multi-Target LSTM-Based Neural Network Regressor

Mathematics ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 2233
Author(s):  
Alessandro Crivellari ◽  
Euro Beinat
Keyword(s):  
Neural Network ◽  
Traffic Control ◽  
Urban Areas ◽  
Short Term Memory ◽  
Urban Traffic ◽  
Entry And Exit ◽  
Short Term ◽  
Spatially Distributed ◽  
Traffic Volumes ◽  
The City

Monitoring the distribution of vehicles across the city is of great importance for urban traffic control. In particular, information on the number of vehicles entering and leaving a city, or moving between urban areas, gives a valuable estimate on potential bottlenecks and congestions. The possibility of predicting such flows in advance is even more beneficial, allowing for timely traffic management strategies and targeted congestion warnings. Our work is inserted in the context of short-term forecasting, aiming to predict rapid changes and sudden variations in the traffic volume, beyond the general trend. Moreover, it concurrently targets multiple locations in the city, providing an instant prediction outcome comprising the future distribution of vehicles across several urban locations. Specifically, we propose a multi-target deep learning regressor for simultaneous predictions of traffic volumes, in multiple entry and exit points among city neighborhoods. The experiment focuses on an hourly forecasting of the amount of vehicles accessing and moving between New York City neighborhoods through the Metropolitan Transportation Authority (MTA) bridges and tunnels. By leveraging a single training process for all location points, and an instant one-step volume inference for every location at each time update, our sequential modeling approach is able to grasp rapid variations in the time series and process the collective information of all entry and exit points, whose distinct predicted values are outputted at once. The multi-target model, based on long short-term memory (LSTM) recurrent neural network layers, was tested on a real-world dataset, achieving an average prediction error of 7% and demonstrating its feasibility for short-term spatially-distributed urban traffic forecasting.

scholarly journals Returning home to die: Circular labour migration and mortality in South Africa 1

2007 ◽  
Vol 35 (69_suppl) ◽  
pp. 35-44 ◽  
Author(s):  
Samuel J. Clark ◽  
Mark A. Collinson ◽  
Kathleen Kahn ◽  
Kyle Drullinger ◽  
Stephen M. Tollman
Keyword(s):  
South Africa ◽  
Rural Areas ◽  
Urban Areas ◽  
Terminal Illness ◽  
Event History Analysis ◽  
Historical Period ◽  
Short Term ◽  
History Analysis ◽  
Working Age

Aim: To examine the hypothesis that circular labour migrants who become seriously ill while living away from home return to their rural homes to convalesce and possibly to die. Methods: Drawing on longitudinal data collected by the Agincourt health and demographic surveillance system in rural northeastern South Africa between 1995 and 2004, discrete time event history analysis is used to estimate the likelihood of dying for residents, short-term returning migrants, and long-term returning migrants controlling for sex, age, and historical period. Results: The annual odds of dying for short-term returning migrants are generally 1.1 to 1.9 times (depending on period, sex, and age) higher than those of residents and long-term returning migrants, and these differences are generally highly statistically significant. Further supporting the hypothesis is the fact that the proportion of HIV/TB deaths among short-term returning migrants increases dramatically as time progresses, and short-term returning migrants account for an increasing proportion of all HIV/TB deaths. Conclusions: This evidence strongly suggests that increasing numbers of circular labour migrants of prime working age are becoming ill in the urban areas where they work and coming home to be cared for and eventually to die in the rural areas where their families live. This shifts the burden of caring for them in their terminal illness to their families and the rural healthcare system with significant consequences for the distribution and allocation of health care resources.

Early short-term continuous high-volume haemofiltration improves clinical outcomes of severe acute pancreatitis

Pancreatology ◽  
2013 ◽  
Vol 13 (3) ◽  
pp. S68
Author(s):  
Wei Huang ◽  
Jia Guo ◽  
Xiao Yang ◽  
Tao Jin ◽  
Kiran Altaf ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Clinical Outcomes ◽  
Severe Acute Pancreatitis ◽  
High Volume ◽  
Short Term

scholarly journals Regional Scale Impact of the COVID-19 Lockdown on Air Quality: Gaseous Pollutants in the Po Valley, Northern Italy

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 264 ◽  
Author(s):  
Giovanni Lonati ◽  
Federico Riva
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Regional Scale ◽  
High Volume ◽  
Ambient Air ◽  
Northern Italy ◽  
Traffic Emissions ◽  
Gaseous Pollutants ◽  
Po Valley ◽  
Concentration Levels

The impact of the reduced atmospheric emissions due to the COVID-19 lockdown on ambient air quality in the Po Valley of Northern Italy was assessed for gaseous pollutants (NO2, benzene, ammonia) based on data collected at the monitoring stations distributed all over the area. Concentration data for each month of the first semester of 2020 were compared with those of the previous six years, on monthly, daily, and hourly bases, so that pre, during, and post-lockdown conditions of air quality could be separately analyzed. The results show that, as in many other areas worldwide, the Po Valley experienced better air quality during 2020 spring months for NO2 and benzene. In agreement with the reductions of nitrogen oxides and benzene emissions from road traffic, estimated to be −35% compared to the regional average, the monthly mean concentration levels for 2020 showed reductions in the −40% to −35% range compared with the previous years, but with higher reductions, close to −50%, at high-volume-traffic sites in urban areas. Conversely, NH3 ambient concentration levels, almost entirely due the emissions of the agricultural sector, did not show any relevant change, even at high-volume-traffic sites in urban areas. These results point out the important role of traffic emissions in NO2 and benzene ambient levels in the Po Valley, and confirm that this region is a rather homogeneous air basin with urban area hot-spots, the contributions of which add up to a relatively high regional background concentration level. Additionally, the relatively slow response of the air quality levels to the sudden decrease of the emissions due to the lockdown shows that this region is characterized by a weak exchange of the air masses that favors both the build-up of atmospheric pollutants and the development of secondary formation processes. Thus, air quality control strategies should aim for structural interventions intended to reduce traffic emissions at the regional scale and not only in the largest urban areas.

Actually Existing Platformization

2021 ◽  
Vol 120 (4) ◽  
pp. 715-731
Author(s):  
Niels van Doorn ◽  
Eva Mos ◽  
Jelke Bosma
Keyword(s):  
Urban Areas ◽  
Boundary Work ◽  
Voluntary Sector ◽  
Food Delivery ◽  
Social Mobilization ◽  
Short Term ◽  
Urban Settings ◽  
The Social ◽  
Path Dependent ◽  
Market Consolidation

In this article we examine the partnership as a heterogeneous boundary resource that enables platforms to generate dependencies, become locally embedded, and gain power in urban settings. Pushing back against narratives of platform-driven disruption, which tend to universalize and totalize platform power, we discuss three cases of what we term “actually existing platformization”—a path-dependent and locally situated process in which platform companies engage in various forms of “boundary work” with other actors seeking to retain and/or gain power. Each case focuses on a distinct industry: food delivery, short-term housing rental, and the social/voluntary sector. In each of these domains, we show how asset-light platforms initiate and develop partnerships as a frequently nebulous boundary resource that opens up potential avenues for (1) market consolidation, (2) logistical integration, (3) social mobilization, and/or (4) institutional legitimation. Such strategic moves, we argue, have become particularly pertinent following the COVID-19 pandemic, which has hit urban areas particularly hard and is intensifying certain social dependencies and institutional shortcomings that platforms are seeking to exploit.

FACTORS AFFECTING URBAN AGRICULTURE DEVELOPMENT IN THAI NGUYEN PROVINCE, VIET NAM

2021 ◽  
Vol 9 (1) ◽  
pp. 222-233
Author(s):  
Vu Bach Diep ◽  
Dinh Hong Linh ◽  
Bui Thi Minh Hang
Keyword(s):  
Urban Agriculture ◽  
Urban Areas ◽  
Industrial Development ◽  
Agricultural Development ◽  
Agricultural Land ◽  
Primary Data ◽  
Factors Affecting ◽  
Infrastructure Policy ◽  
Process Of Urbanization ◽  
Agriculture Development

The process of urbanization is taking place fast and vigorously in large urban and peri-urban areas in Vietnam. According to national forecasts, the rate of urbanization nationwide will reach 39.3% by 2020 and 50-55% by 2035. Thai Nguyen is a province in the midland and mountainous region. The province is located at the northern gateway and bordered with Hanoi capital. In recent years, the agricultural land area of Thai Nguyen province has narrowed due to the urban-industrial development. Urban agriculture development is an inevitable direction, creating safe and high quality food products, protecting the ecological environment, and increasing people's income. Thai Nguyen is one of the provinces promoting sustainable urban agricultural development. Secondary and primary data sources are analyzed and synthesized by descriptive statistical methods. The article will analyze five groups of factors affecting urban agricultural development in Thai Nguyen province in the period 2015-2018, including Socio-economic; Natural conditions and infrastructure; Policy factors; Planning factors; Links and integration.

scholarly journals 2 + 1 Highways: Overview and Future Directions

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Manuel Romana ◽  
Marilo Martin-Gasulla ◽  
Ana T. Moreno
Keyword(s):  
Urban Areas ◽  
High Performance ◽  
White Paper ◽  
Future Directions ◽  
Research Directions ◽  
Traffic Volumes ◽  
Primary Means ◽  
The Common ◽  
Rural Access ◽  
Transportation Research

Most of the rural transportation system is composed of two-lane highways, and many of them serve as the primary means for rural access to urban areas and freeways. In some highways, traffic volumes can be not high enough to justify a four-lane highway but higher than can be served by isolated passing lanes, or can present high number of head-on collisions. In those conditions, 2 + 1 highways are potentially applicable. This type of highway is used to provide high-performance highways as intermediate solution between the common two-lane highway and the freeway. Successful experiences reported in Germany, Sweden, Finland, Poland, or Texas (US) may suggest that they are potentially applicable in other countries. The objective of this white paper is to provide an overview of the past practice in 2 + 1 highways and discuss the research directions and challenges in this field, specially focusing on, but not limited to, operational research in association with the activities of the Subcommittee on Two-Lane Highways (AHB40 2.2) of the Transportation Research Board. The significance of this paper is twofold: (1) it provides wider coverage of past 2 + 1 highways design and evaluation, and (2) it discusses future directions of this field.

Sign in / Sign up

Export Citation Format

Share Document