scholarly journals Traffic Operations on Rural Two-Lane Highways: A Review on Performance Measures and Indicators

2018 ◽  
Vol 2672 (15) ◽  
pp. 66-74 ◽  
Author(s):  
Ahmed Al-Kaisy ◽  
Amirhossein Jafari ◽  
Scott Washburn ◽  
Tapio Lutinnen ◽  
Richard Dowling
Keyword(s):  
United States ◽  
Performance Measures ◽  
Rural Areas ◽  
Subjective Assessment ◽  
The United States ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Improvement Programs ◽  
Performance Determinants ◽  
Highway Facilities

Two- lane highways constitute a large proportion of the highway system in the United States, particularly in rural areas. Performance evaluation on those highways is the basis for planning, upgrade, and improvement programs. Such evaluations are conducted using performance measures that should ideally be correlated to performance determinants on those highways. Unlike other highway facilities, two-lane highway performance is notably affected by the platooning phenomenon, which is believed to be a function of traffic level and passing opportunities. Over the last couple of decades, several studies have addressed performance measures on two-lane highways, and are mainly driven by the reported limitations of the current measures used by the Highway Capacity Manual (HCM). This review aims to summarize the performance measures that have been published in the literature or used in practice both in the United States and abroad. The review starts with an historical overview of the HCM performance measures since its inception in 1950. It then discusses the most important criteria for measures to be more effective in describing performance, before presenting the review results for measures that have been proposed in literature or reported as being used in practice. Finally, a subjective assessment of all performance measures against the set of criteria outlined in the article is presented. The review presented in this paper provides information that is valuable for practitioners and researchers in understating the alternative measures for assessing performance on two-lane highways, and the limitations and merits associated with those measures.

Freeway Weaving: Comparison of Highway Capacity Manual 2000 and Dutch Guidelines

2003 ◽  
Vol 1852 (1) ◽  
pp. 10-18 ◽  
Author(s):  
M. M. Minderhoud ◽  
L. Elefteriadou Elefteriadou
Keyword(s):  
United States ◽  
Sensitivity Analysis ◽  
The United States ◽  
Level Of Service ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Additional Variable ◽  
Different Types ◽  
The U.S ◽  
Capacity Estimates

Weaving sections are a commonly adopted freeway facility both in the United States and in Europe. Knowledge about the capacity and level of service achievable on different types of weaving segments is necessary for the design and management of freeways. Guidelines such as those of the U.S. Highway Capacity Manual (HCM) provide capacity values for different weaving configuration types. The Dutch guidelines for the design of weaving segments are compared with those of the U.S. HCM. Differences between their respective approaches are identified, and a comparison of capacity values is conducted. It was found that there are large differences in capacity estimates for certain weaving configuration types. The results of a sensitivity analysis explain these differences in capacity values to a large extent. This analysis showed that it is important to consider the weaving proportions per leg. Currently, neither the HCM nor the Dutch approach considers different weaving flows per incoming leg. The introduction of an additional variable into the calculation procedure that takes into account the presence of asymmetrical weaving flows is recommended.

Lane Utilization Model Development for Diverging Diamond Interchanges

2017 ◽  
Vol 2618 (1) ◽  
pp. 27-37
Author(s):  
Chunho Yeom ◽  
Bastian J. Schroeder ◽  
Christopher Cunningham ◽  
Katy Salamati ◽  
Nagui M. Rouphail
Keyword(s):  
United States ◽  
Field Data ◽  
Model Development ◽  
The United States ◽  
Highway Capacity ◽  
Double Crossover ◽  
Highway Capacity Manual ◽  
Diamond Interchanges ◽  
Lane Utilization ◽  
Analysis Models

The diverging diamond interchange (DDI), also known as the double crossover diamond interchange, has been a successful, if unconventional, solution used in many parts of the United States ever since its first installation in Springfield, Missouri, in June 2009. One of the challenges to agencies in planning and operating DDIs is to apply to them methodologies developed for a conventional diamond interchange. The Highway Capacity Manual 2010 (HCM 2010) provides lane use analysis models for various lane configurations. However, there is no guarantee that these models will work for DDIs. For this reason, 11 DDIs were studied nationwide ( a) to examine whether the current HCM lane use models provided accurate results for DDIs and ( b) to develop new lane use models for them if the HCM models did not work. As a result of the study, unique multiregime lane utilization models were proposed, separated by the number of approach lanes and validated by field data not used in the model development.

Safety, Delay, and Capacity of Single-Lane Roundabouts in the United States

1998 ◽  
Vol 1646 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Aimee Flannery ◽  
Lily Elefteriadou ◽  
Paul Koza ◽  
John McFadden
Keyword(s):  
United States ◽  
Field Capacity ◽  
Traffic Signals ◽  
The United States ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Control Delay ◽  
Capacity Model ◽  
Potential Capacity ◽  
Before And After

Roundabouts are a form of at-grade intersection control that is used frequently around the world and is becoming popular in the United States. Roundabouts are being used to replace two-way and all-way stopcontrolled intersections and traffic signals in the United States. Roundabouts have also been used recently in Vail, Colorado, to improve an existing stop-controlled freeway interchange system. In this study, five single-lane roundabouts are studied to assess their safety and operational performance. All five sites were stop-controlled before roundabouts were installed, and overall the sites experienced a reduction in accident frequencies, rates, and also control delay. Aside from a review of safety and delay data before and after installation of the roundabouts, this study includes a comparison of field-measured control delay with that predicted by SIDRA, an analytically based software package that can analyze at-grade sign- and signal-controlled intersections as well as roundabouts. This study will help agencies better understand their ability to predict delay at American roundabouts. Finally, findings are presented regarding the accuracy of the roundabout capacity model contained in the 1997 update to Chapter 10 of the Highway Capacity Manual. Because of the lack of roundabout entries that are operating at capacity in the United States, an approximation of potential capacity based on available gaps in the circulating stream was made. These findings indicate that the manual may be optimistic in its prediction of capacity for single-lane roundabouts in the United States; however, it should be noted that the lack of roundabout entries operating under capacity in the United States only allows for an approximation of field capacity to be made at this time.

scholarly journals Deriving Operational Traffic Signal Performance Measures from Vehicle Trajectory Data

2021 ◽  
pp. 036119812110067
Author(s):  
Enrique Saldivar-Carranza ◽  
Howell Li ◽  
Jijo Mathew ◽  
Margaret Hunter ◽  
James Sturdevant ◽  
...  
Keyword(s):  
Performance Measures ◽  
Capital Investment ◽  
The United States ◽  
Traffic Signal ◽  
Trajectory Data ◽  
Highway Capacity ◽  
Highway Capacity Manual ◽  
Annual Average Daily Traffic ◽  
Vehicle Trajectory

Operations-oriented traffic signal performance measures are important for identifying the need for retiming to improve traffic signal operations. Currently, most traffic signal performance measures are obtained from high-resolution traffic signal controller event data, which provides information on an intersection-by-intersection basis and requires significant initial capital investment. Over 400 billion vehicle trajectory points are generated each month in the United States. This paper proposes using high-fidelity vehicle trajectory data to produce traffic signal performance measures such as: split failure, downstream blockage, and quality of progression, as well as traditional Highway Capacity Manual level of service. Geo-fences are created at specific signalized intersections to filter vehicle waypoints that lie within the generated boundaries. These waypoints are then converted into trajectories that are relative to the intersection. A case study is presented that summarizes the performance of an eight-intersection corridor with four different timing plans using over 160,000 trajectories and 1.4 million GPS samples collected during weekdays in July 2019 between 5:00 a.m. and 10:00 p.m. The paper concludes by commenting on current probe data penetration rates, indicating that these techniques can be applied to corridors with annual average daily traffic of ~15,000 vehicles per day for the mainline approaches, and discussing cloud-based implementation opportunities.

Weight Identity Among Older Adults in the United States: Genetic and Environmental Influences

2018 ◽  
pp. 262-274
Author(s):  
Robbee Wedow ◽  
Daniel A. Briley ◽  
Susan E. Short ◽  
Jason Boardman
Keyword(s):  
United States ◽  
Older Adults ◽  
Social Identity ◽  
Weight Status ◽  
Environmental Influences ◽  
Subjective Assessment ◽  
The United States ◽  
Men And Women ◽  
Perceived Weight ◽  
Midlife Adults

This chapter uses twin pairs from the Midlife in the United States study to investigate the genetic and environmental influences on perceived weight status for midlife adults. The inquiry builds on previous work investigating the same phenomenon in adolescents, and it shows that perceived weight status is not only heritable, but also heritable beyond objective weight. Subjective assessment of physical weight is independent of one’s physical weight and described as “weight identity.” Importantly, significant differences are shown in the heritability of weight identity among men and women. The chapter ends by discussing the potential relevance of these findings for broader social identity research.

scholarly journals Factors Influencing Land Values in the Presence of Suburban Sprawl

1974 ◽  
Vol 3 (1) ◽  
pp. 112-124 ◽  
Author(s):  
Bruce E. Lindsay ◽  
Cleve E. Willis
Keyword(s):  
United States ◽  
Rural Areas ◽  
The United States ◽  
Land Values ◽  
Suburban Sprawl ◽  
Factors Influencing ◽  
Definition Of

The spread of suburbs into previously rural areas has become commonplace in the United States. A rather striking aspect of this phenomenon has been the discontinuity which results. This aspect is often manifest in a haphazard mixture of unused and densely settled areas which has been described as “sprawl”. A more useful definition of suburban sprawl, its causes, and its consequences, is provided below in order to introduce the econometric objectives of this paper.

scholarly journals Italianness in the United States between migrants’ informal gardening practices and agricultural diplomacy (1880–1912)

Modern Italy ◽  
2021 ◽  
pp. 1-17
Author(s):  
Gilberto Mazzoli
Keyword(s):  
United States ◽  
Environmental History ◽  
Rural Areas ◽  
Food Production ◽  
East Coast ◽  
The United States ◽  
Southern United States ◽  
Mass Migration ◽  
Us Cities ◽  
Political Radicalism

During the Age of Mass Migration more than four million Italians reached the United States. The experience of Italians in US cities has been widely explored: however, the study of how migrants adjusted in relation to nature and food production is a relatively recent concern. Due to a mixture of racism and fear of political radicalism, Italians were deemed to be undesirable immigrants in East Coast cities and American authorities had long perceived Italian immigrants as unclean, unhealthy and carriers of diseases. As a flipside to this narrative, Italians were also believed to possess a ‘natural’ talent for agriculture, which encouraged Italian diplomats and politicians to propose the establishment of agricultural colonies in the southern United States. In rural areas Italians could profit from their agricultural skills and finally turn into ‘desirable immigrants’. The aim of this paper is to explore this ‘emigrant colonialism’ through the lens of environmental history, comparing the Italian and US diplomatic and public discourses on the potential and limits of Italians’ agricultural skills.

scholarly journals PM2.5 polluters disproportionately and systemically affect people of color in the United States

2021 ◽  
Vol 7 (18) ◽  
pp. eabf4491
Author(s):  
Christopher W. Tessum ◽  
David A. Paolella ◽  
Sarah E. Chambliss ◽  
Joshua S. Apte ◽  
Jason D. Hill ◽  
...  
Keyword(s):  
United States ◽  
Rural Areas ◽  
The United States ◽  
People Of Color ◽  
Emission Sources ◽  
Particulate Air Pollution ◽  
Fine Particulate ◽  
Exposure Levels ◽  
Urban And Rural Areas ◽  
Racial Ethnic

Racial-ethnic minorities in the United States are exposed to disproportionately high levels of ambient fine particulate air pollution (PM2.5), the largest environmental cause of human mortality. However, it is unknown which emission sources drive this disparity and whether differences exist by emission sector, geography, or demographics. Quantifying the PM2.5 exposure caused by each emitter type, we show that nearly all major emission categories—consistently across states, urban and rural areas, income levels, and exposure levels—contribute to the systemic PM2.5 exposure disparity experienced by people of color. We identify the most inequitable emission source types by state and city, thereby highlighting potential opportunities for addressing this persistent environmental inequity.

scholarly journals Strategies for Disseminating and Implementing the COVID-19 Vaccines in Rural Areas

2021 ◽  
Author(s):  
Beth Prusaczyk
Keyword(s):  
United States ◽  
Health Disparities ◽  
Urban Health ◽  
Rural Areas ◽  
The United States ◽  
Urban Residents ◽  
Rural Residents ◽  
Vaccination Programs ◽  
Vaccine Information ◽  
Roll Out

Abstract The United States has well-documented rural-urban health disparities and it is imperative that these are not exacerbated by an inefficient roll-out of the COVID-19 vaccines to rural areas. In addition to the pre-existing barriers to delivering and receiving healthcare in rural areas, such as high patient:provider ratios and long geographic distances between patients and providers, rural residents are significantly more likely to say they have no intention of receiving a COVID-19 vaccine, compared to urban residents. To overcome these barriers and ensure rural residents receive the vaccine, officials and communities should look to previous research on how to communicate vaccine information and implement successful vaccination programs in rural areas for guidance and concrete strategies to use in their local efforts.

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