Speed-Profile Model for a Design-Consistency Evaluation Procedure in the United States

2000 ◽  
Vol 1701 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Jeffery L. Ottesen ◽  
Raymond A. Krammes
Keyword(s):  
United States ◽  
The United States ◽  
Evaluation Procedure ◽  
Preliminary Evaluation ◽  
Speed Profile ◽  
Evaluation Tool ◽  
Rural Highways ◽  
Profile Model ◽  
Horizontal Curves ◽  
Design Consistency

A speed-profile model for estimating 85th percentile speeds along horizontal alignments of rural two-lane highways in the United States is documented. The model is an evaluation tool to check for speed consistency violations on alignments with design speeds less than 100 km/h (62.1 mph). The model was calibrated by using speed and geometry data collected for 138 horizontal curves and 78 approach tangents on 29 rural highways in 5 states. A preliminary evaluation suggests that the model provides reasonable estimates of the reductions in 85th percentile speeds from an approach tangent to a horizontal curve.

Improved speed-profile model for two-lane rural highways

2003 ◽  
Vol 30 (6) ◽  
pp. 1055-1065 ◽  
Author(s):  
Said M Easa
Keyword(s):  
Highway Safety ◽  
Extended Model ◽  
Speed Profile ◽  
Rural Highways ◽  
Profile Model ◽  
Horizontal Curves ◽  
Sight Distance ◽  
Safety Design ◽  
Speed Change ◽  
Design Consistency

The speed-profile model has been suggested as a valuable tool for evaluating geometric design consistency for two-lane rural highways with isolated and combined horizontal and vertical alignments. The model determines the operating speeds on the speed-change (SC) segment, which is the distance between speed-limiting curves. The speed-limiting curves are the horizontal curves and the limited sight-distance crest vertical curves on horizontal tangents, where the sight distance required by the design guides is not satisfied. The model assumes that deceleration begins where required, which implies that the next curve is visible when deceleration starts. This paper presents an extension to the speed-profile model to incorporate the effect of sight obstruction on operating speeds and deceleration rates. The SC segment may include nonlimited sight–distance crest vertical and sag vertical curves. These curves may present sight obstruction. A procedure to determine whether the sight line is obstructed is developed. If it does, simple formulas are applied for revising the operating-speed profile. The extended model is suitable for inclusion in the design consistency module of the interactive highway safety design model.Key words: speed profile, model, two-lane highways, alignments, design consistency.

Preliminary Validation of a Speed-Profile Model for Design Consistency Evaluation

1996 ◽  
Vol 1523 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Kent M. Collins ◽  
Raymond A. Krammes
Keyword(s):  
Speed Profile ◽  
Rural Highways ◽  
Speed Reduction ◽  
Profile Model ◽  
Horizontal Curves ◽  
Preliminary Validation ◽  
Design Consistency ◽  
Consistency Evaluation

The validity of a speed-profile model for design consistency evaluation was tested, including (a) the speed reduction estimation ability of the model and (b) assumptions about deceleration and acceleration characteristics approaching and departing horizontal curves. Detailed speed data were collected at a sample of 10 horizontal tangent-curve sections on two-lane rural highways in Texas. The results indicate that the model provides a reasonable, albeit simplified, representation of speed profiles on horizontal alignments consisting of long tangents and isolated curves. The model provides reasonable estimates of speed reductions from long approach tangents to curves but does not account for the effect of nearby intersections on speeds. The results also indicate that the assumed 0.85 m/sec2 value is reasonable for deceleration rates approaching curves that require speed reductions but may overestimate acceleration rates departing curves. The model's assumptions that deceleration occurs entirely on the approach tangent and that speeds are constant throughout a curve were not confirmed by observed speed behavior. The observations that deceleration continues after entering a curve and that speed adjustments occur throughout a curve are indicators of the difficulty drivers experience in judging appropriate speeds through curves.

Speed-Profile Model for Two-Lane Rural Highways

2000 ◽  
Vol 1737 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Kay Fitzpatrick ◽  
Jon M. Collins
Keyword(s):  
Highway Safety ◽  
Geometric Features ◽  
Speed Profile ◽  
Model Design ◽  
Rural Highways ◽  
Profile Model ◽  
Safety Design ◽  
Acceleration And Deceleration ◽  
Speed Prediction ◽  
Design Consistency

Design consistency refers to highway geometry’s conformance with driver expectancy. Generally, drivers make fewer errors at geometric features that conform with their expectations. A proposed method for evaluating design consistency is to predict the speed along an alignment by using a speed-profile model. A speed-profile model was developed by using the following: speed prediction equations that calculate the expected speed at horizontal, vertical, or combination curves; assumed desired speed for the roadway; TWOPAS equations that determine the performance-limited speeds at every point; acceleration and deceleration rates; and several documented assumptions. The speed-profile model can be used to evaluate the design consistency of a facility or to generate a speed profile along an alignment. In conclusion, the speed-profile model developed appears to provide a suitable basis for the Interactive Highway Safety Design Model design consistency module.

scholarly journals A comparison of sleep, depressive symptoms, and parental perceptions between U.S. and Taiwan adolescents with self-reported sleep problems

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Ya-Ting Yang ◽  
Katherine A Kaplan ◽  
Jamie M Zeitzer
Keyword(s):  
United States ◽  
Depressive Symptoms ◽  
Sleep Problems ◽  
The United States ◽  
Preliminary Evaluation ◽  
Sleep Behavior ◽  
Behavioral Choices ◽  
Antecedents And Consequences ◽  
Inadequate Sleep ◽  
Better Than

Abstract Study Objectives Inadequate sleep is pervasive among teens worldwide, resulting in daytime sleepiness and, in some cases, depressive symptoms. In addition to their own behavioral choices, parent perceptions may also play a role in adolescent sleep. This study conducted a preliminary evaluation of the antecedents and consequences of sleep factors among adolescents in the United States and Taiwan. Methods Participants were adolescents with self-reported sleep concerns from academically similar schools in Taiwan (n = 548) and northern California, United States (n = 128). Questionnaires on sleep and mood were administered to both the teens and parents. Results While Taiwanese students’ self-reported sleep behavior was generally better than U.S. students (p < .01), Taiwanese students had higher overall self-reported sleepiness (p < .01). Furthermore, Taiwanese parents reported teen sleep durations of 6.53 ± .827 hours per night during the week (with 45% perceiving this as sufficient), while U.S. parents reported teen sleep durations of 7.22 ± .930 hours (with 27% perceiving this as sufficient). Adolescents in both cohorts had high levels of symptoms consistent with depression (Taiwan: 70%, United States: 62%), which was associated with shorter sleep times for both cohorts and evening chronotype in the Taiwanese, but not U.S., adolescents. Conclusions Some differences exist between Taiwanese and U.S. adolescents, with generally better sleep and less sleepiness reported among students in the United States, and Taiwanese students’ sleep influenced more strongly by chronotype. Furthermore, Taiwanese parents reported less concern about their child’s insufficient sleep, despite the fact that inadequate sleep is strongly associated with depressive symptoms for both cohorts.

Establishing highway horizontal alignment to maximize design consistency

2007 ◽  
Vol 34 (9) ◽  
pp. 1159-1168 ◽  
Author(s):  
Said M Easa ◽  
Atif Mehmood
Keyword(s):  
Geometric Features ◽  
Trial And Error ◽  
Highway Design ◽  
Rural Highways ◽  
Physical Constraints ◽  
Horizontal Alignment ◽  
Horizontal Curves ◽  
Decision Variables ◽  
Acceleration And Deceleration ◽  
Design Consistency

Highway design consistency is one of the important criteria in selecting the geometric features of proposed or existing alignments of two-lane rural highways. Operating-speed (OS) profile models have been used to evaluate design consistency by trial and error. For a proposed new highway, however, there may be geometric and physical constraints, and selection of these elements by trial and error to achieve optimal design consistency would be difficult, if not impossible. This paper presents an optimization model that establishes highway horizontal alignment to achieve maximum design consistency based on the OS profile. The decision variables of the model include radius of horizontal curves, spiral curve lengths, length of speed-change (SC) segments, and acceleration and deceleration rates. The objective function of the model minimizes the mean OS difference or the maximum OS difference for successive geometric features along the highway section. Application examples and sensitivity analysis are presented to illustrate the capabilities of the model in evaluating improvement strategies and to ensure that the model produces sound optimum alignments. The proposed model, which complements existing optimization models that mainly address highway construction cost, should be of interest to highway practitioners and engineers.Key words: design consistency, highway, geometric, horizontal alignment, optimization modeling, speed profile.

Government-Sponsored Research in International Studies

1970 ◽  
Vol 22 (4) ◽  
pp. 582-596
Author(s):  
Cyril E. Black
Keyword(s):  
United States ◽  
Research Policy ◽  
International System ◽  
The United States ◽  
Significant Degree ◽  
Preliminary Evaluation ◽  
International Studies ◽  
The People ◽  
Critical Issues ◽  
Support Of Research

The purpose of this paper is to make a preliminary evaluation of the pattern of support of research in international studies in the United States by federal agencies, with a view to identifying critical issues in research policy deserving of more detailed study.The security and welfare of the people of the United States depend to a significant degree on the quality of the system of knowledge available to their leaders and to the community of scholars on whose advice regarding the international system in all of its aspects their leaders depend.

scholarly journals Addition of Care for Transgender-Related Patient Care into Doctorate of Pharmacy Curriculum: Implementation and Preliminary Evaluation

Pharmacy ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 107 ◽  
Author(s):  
Cheyenne Newsome ◽  
Li-Wei Chen ◽  
Jessica Conklin
Keyword(s):  
United States ◽  
Patient Care ◽  
The United States ◽  
Preliminary Evaluation ◽  
Learning Session ◽  
Transgender People ◽  
Cultural Empathy ◽  
Before And After ◽  
And Gender ◽  
Pharmacy Curriculum

The number of transgender and gender-diverse patients seeking medical care in the United States is increasing. For many of these patients, pharmacotherapy is a part of their gender-affirming transition. Effective instructional methods and resources for teaching pharmacy students about this patient population’s social considerations and medical treatments is lacking. Three hours of educational material on caring for transgender patients was added to a third-year course in a four-year Doctorate of Pharmacy program in the United States. The content included cultural, empathy, and medical considerations. Students in the course were given a survey to assess their perception of each instructional method’s effectiveness and self-assess their confidence in providing competent gender-affirming care to transgender people before and after the learning session. The survey response rate was 36% (54/152). Students’ self-assessed confidence to provide competent care to people who are transgender increased significantly. Before the learning session, the median confidence level was 4/10 (Interquartile range (IQR) 3–6), after the class session, the median confidence increased to 7/10 (IQR 6–8, p < 0.01). Students rated the pre-class video, jeopardy game, and patient panel as most helpful to improving their skills. The addition of transgender-related patient care material into the Doctorate of Pharmacy curriculum significantly increased the students’ confidence to provide competent care to people who are transgender.

A Case Study: Harmonization of Veterinary Drug Maximum Residue Levels Between the U.S. and Canada

1996 ◽  
Vol 15 (5) ◽  
pp. 436-444
Author(s):  
Steven D. Brynes ◽  
Richard H. Teske
Keyword(s):  
United States ◽  
Working Group ◽  
Daily Intake ◽  
The United States ◽  
Veterinary Drugs ◽  
Evaluation Procedure ◽  
Veterinary Drug ◽  
The Us ◽  
Maximum Residue Levels ◽  
Residue Levels

The Free Trade Agreement between the United States and Canada (FTA) went into effect January 1, 1989. To implement certain provisions of the agreement on technical regulations and standards, the United States Center for Veterinary Medicine, the Canadian Bureau of Veterinary Drugs, and Agriculture Canada established the Working Group on Veterinary Drug Tolerances. The primary charges to the Working Group on Veterinary Drug Tolerances were (1) to harmonize the procedures used for evaluating new animal drugs, performing risk assessments and calculating tolerances, and (2) to harmonize the tolerances (or maximum residue levels, MRLs) for approved drugs, with the goal of having the same tolerances in each country. The first of these charges was met early in the negotiations. Both the US and Canada will use a 6-step evaluation procedure for the human food safety evaluation of new animal drugs. On September 29, 1990, Canada published a list of MRLs for 38 drugs that had been harmonized through the FTA. The progress of the working group and its continuing efforts to harmonize tolerances for approximately 15 other veterinary drugs will be discussed. This paper proposes use of the toxicologically determined acceptable daily intake (ADI) for the drug as the safety standard for reaching conclusions on the acceptability of residues in meat for human consumption. Specifically, the ‘equivalence’ of different MRLs for the same veterinary drug would be determined by considering whether they are likely to result in dietary residues that exceed the other country's ADI for the drug. Estimates are made for the veterinary drugs lasalocid and halofuginone hydrobromide. Based on these estimates, the US and Canadian MRLs for each drug would be considered ‘equivalent’ for trade purposes.

Verification of usRAP Risk Assessments for Run-Off and Head-On Crashes Using Field Data

2021 ◽  
pp. 036119812110322
Author(s):  
Fahmid Hossain ◽  
Juan C. Medina
Keyword(s):  
United States ◽  
The United States ◽  
Risk Assessments ◽  
Crash Data ◽  
Horizontal Curves ◽  
Crash Rates ◽  
Run Off ◽  
Fatal Crashes ◽  
Safety Assessments ◽  
Safety Applications

The United States Road Assessment Program (usRAP) provides a systemic approach to estimate the risk of severe injury and fatal crashes along roadway segments based on the expected safety performance of roadway and roadside characteristics, together with a general estimation of traffic volume. Detailed crash data are not needed for safety assessments, providing advantages over more traditional crash-driven approaches. However, experiences with usRAP are limited to the United States and to date, the program has a growing but limited number of participating states. Verification of the adequacy of usRAP assessments is therefore of significant value, not only to identify strengths and limitations of the methodology within the U.S. context, but also to potentially expand the set of tools available to agencies. This paper presents a verification of usRAP risk assessments for run-off-road and head-on crashes using over 7,000 mi of coded segments and five years of crash data collected in Utah. Comparisons between risk estimations from usRAP and actual crash rates provided insights into the expected and observed effects of roadside objects and their distances from the lanes traveled, type of median present, and horizontal curves. A spatial correlation test also confirmed the agreement between usRAP risk assessments and crash data, providing additional promising indications of the suitability of this systemic methodology for safety applications.

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