Operating Speed on a Buffer-Separated Managed Lane

2017 ◽  
Vol 2616 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Kay Fitzpatrick ◽  
Raul Avelar ◽  
Tomás E. Lindheimer
Keyword(s):  
Los Angeles ◽  
Orange County ◽  
General Purpose ◽  
Operational Performance ◽  
Left Shoulder ◽  
Operating Speed ◽  
Managed Lanes ◽  
Lane Width ◽  
Buffer Width ◽  
The Relationship

Managed lanes typically are on or adjacent to freeways and are actively operated and managed to preserve operational performance—such as more optimal travel speeds—over comparable general-purpose traffic lanes. A study was conducted to evaluate speeds on existing buffer-separated managed lanes to identify variables that influence operating speed. Speed data from more than 130 unique sites in Los Angeles, California; Orange County, California; and Dallas, Texas, were used. All analyses showed that the managed lane volume and the speed in the general-purpose lanes were related to the speed in the managed lane (statistically significant). The Dallas analysis, which used speeds averaged by 1-min increments, showed that the factor with the most influence on uncongested managed lane speed was the managed lane’s geometry. The relationship between uncongested managed lane speed and the managed lane envelope (sum of left shoulder width, managed lane width, and buffer width) was found to be statistically significant. For each additional foot over a 16-ft envelope width, managed lane speed increased by approximately 3.2 mph. In contrast, the California analysis, which used speeds averaged by 1-h increments, showed that the variable having the most influence was the volume in the managed lane. The researchers theorized that the lack of a relationship between managed lane speed and geometry in California is related to those speeds being an average 1-h speed rather than the 1-min speeds available in Texas.

Safety Evaluation of Cross-Sectional Elements of Freeway Managed Lanes

2018 ◽  
Vol 2672 (14) ◽  
pp. 20-28 ◽  
Author(s):  
Raul E. Avelar ◽  
Kay Fitzpatrick
Keyword(s):  
Safety Evaluation ◽  
General Purpose ◽  
Left Shoulder ◽  
Managed Lanes ◽  
Cross Sectional ◽  
Federal Highway ◽  
Lane Width ◽  
Severity Levels ◽  
Buffer Width ◽  
The Relationship

This paper investigated the safety implications of managed-lane cross-sectional elements. The objective of the Federal Highway Administration project was to investigate the relationship between crashes and buffer-separated managed lane dimensions. The results from several previous research studies have demonstrated that reductions in freeway lane width or shoulder width are associated with more crashes. This research found that a narrower managed-lane envelope width (i.e., left shoulder, managed-lane, and buffer width combined) is also associated with more freeway crashes for crashes of all severity levels including fatal and injury. Wider envelopes are associated a reduction in total freeway crashes, of all severities, of 2.8% in Texas, and 2.0% in California, for each additional foot of envelope width. In California, wider envelopes are associated with a reduction of 4.4% in managed-lane-related crashes resulting in fatalities and injuries at all severity levels, for each additional foot of envelope width. The analysis was conducted on nonweaving managed-lane segments that included a single managed-lane separated from the general-purpose lanes with a flush buffer area. The dataset included crashes on 128.0 miles of freeway in California (all 128.0 miles with flush buffers) and 60.4 miles of freeway in Texas (41.7 miles with pylon buffers and 18.7 miles with flush buffers). The California sites included freeways with three or four general-purpose lanes, and the Texas freeways had three to five general-purpose lanes.

Economic and Fiscal Impacts of Metropolitan Decentralization: The Southern California Case

1979 ◽  
Vol 11 (6) ◽  
pp. 643-654 ◽  
Author(s):  
H W Richardson ◽  
P Gordon
Keyword(s):  
Los Angeles ◽  
Orange County ◽  
Central City ◽  
Metropolitan Region ◽  
Public Expenditures ◽  
Employment Change ◽  
Study Region ◽  
Relative Proximity ◽  
Fiscal Impacts ◽  
The Relationship

This paper employs a matrix version of the Lowry model to generate spatially disaggregated employment and population impacts. The model is used to study the effects of the decentralization of basic employment in the Los Angeles metropolitan region from its central core to a suburban location in Orange County. Advantage is taken of the fact that the study region comprises a large number of separate fiscal jurisdictions, and so the model is extended to measure the fiscal impacts of the derived population and employment changes associated with this decentralization. It is shown that net impacts hide significant gross expansions and declines that occur at the geographically disaggregated level. The relocation of a given number of basic jobs from Los Angeles to peripheral Orange County has a marked impact on jobs, population, and public expenditures in individual cities, depending on their relative proximity to the sources of basic-employment change. Although the relationship between the central city and the suburbs is highly competitive, the central city may gain from spatial-multiplier impacts if the suburbs (especially close-in suburbs) attract jobs from outside the region.

Effect of Geometric Factors on Lateral Position of Vehicles in Freeway Buffer-Separated Managed Lanes

2017 ◽  
Vol 2616 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Tomás E. Lindheimer ◽  
Kay Fitzpatrick ◽  
Raul Avelar ◽  
Jeffrey D. Miles
Keyword(s):  
Field Studies ◽  
Lateral Position ◽  
Left Shoulder ◽  
Design Element ◽  
Managed Lanes ◽  
Trade Offs ◽  
Buffer Width ◽  
Instrumented Vehicle ◽  
The Right ◽  
The Impact

Chapter 3 in the 2004 AASHTO high-occupancy-vehicle guidelines includes a prioritized trade-off table of various design options for high-occupancy-vehicle lanes (now known as managed lanes). The design trade-offs include the reduction of lane, shoulder, or buffer width. The key measure thought to be affected by lane, shoulder, and buffer width is lateral position. The presented study identified the relationship between operations and cross-section width, including the type of buffer design separating the managed lanes from the general-purpose lanes. This research study collected lateral position data on existing managed lane facilities with a range of geometric elements within both tangent and horizontal curves and identified potential relationships between the geometric design element values and the measure of effectiveness. The field studies included data collected at 28 sites with fixed video cameras and along 161 centerline miles with an instrumented vehicle that recorded data for the vehicle immediately in front of the instrumented vehicle. The study found that managed-lane drivers shifted away from the pylons placed in the buffer. Horizontal alignment (tangent or curve) and the direction of the horizontal curve (left or right) influenced lateral position. Left shoulder, lane, and buffer width affected lateral position. Modifying a 6.5-ft shoulder to a minimum shoulder (i.e., 1.5 ft) will result in drivers moving to the right about 0.5 ft; however, if an 18.5-ft shoulder is reduced by 5 ft, the impact in operations is negligible (drivers would shift only about 0.11 ft toward the right).

Structural Mediation Model of Information System and Sustainable Performance of UAE Manufacturing Sector

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Mohamed Ahmed Darwish Abdulla Larii ◽  
◽  
Fatma Ahmed Lari ◽  
Mohamed Ahmed Darwish Abdulla Lari ◽  
◽  
...  
Keyword(s):  
Information System ◽  
Manufacturing Sector ◽  
Organisational Culture ◽  
The Body ◽  
Mediating Effect ◽  
Operational Performance ◽  
Manufacturing Companies ◽  
Mediation Model ◽  
Sustainable Performance ◽  
The Relationship

This study intends to find out the mediating effect of organisational culture on the relationship between information system and sustainable performance of manufacturing sector in UAE. This study used AMOS-SEM software to develop mediation model that linking the mediating relationships between Information System, Organisational Culture and Sustainable operation Performance. Data was collected through questionnaire survey among the operation staff of Abu Dhabi manufacturing companies. A total 250 questionnaires were distributed however 205 were returned and only 200 are valid which indicates a response rate of 80%. The analysis found that TPS has positive but not significant effect to SP; OIS has positive but not significant effect to SP; FMW has a positive and significant effect on SP; SDS has a negative and not significant effect to SP and SP has positive but not significant effect OC. For the path relationship between the four exogenous variables (TPS, OIS, SDS, and FMW) and the mediator variable (OC), the results are TPS has positive and significant effect to OC; OIS has positive but not significant effect to OC; FMW has positive and significant effect to OC and SDS has positive and not significant effect to OC. Collectively, the five exogenous constructs (TPS, OIS, SDS, FMW and OC) explained 89% variation in operational performance and 86% of the variation in organisational culture. However, for a mediator, it was found that OC has no significant mediating effect on the relationship between TPS and SP; OC has no significant mediating effect on the relationship between OIS and SP; OC has no significant mediating effect on the relationship between SDS and SP and OC has no significant mediating effect on the relationship between FMW and SP. it can be concluded that there is a positive relationship between information system dimensions and operational performance. However organizational culture has no contributing any mediating effect to the relationship. These findings have contributed to the body of knowledge and could be shared among the UAE manufacturing practitioners.

Prehospital Emergency Provider’s Knowledge of and Comfort With Pediatric and Special Needs Cases: A Cross-Sectional Study in Los Angeles County

2021 ◽  
pp. 016327872110039
Author(s):  
Christopher J. Rogers ◽  
Marianne Gausche-Hill ◽  
Laurie Lee Brown ◽  
Rita V. Burke
Keyword(s):  
Health Care ◽  
Los Angeles ◽  
Continuing Education ◽  
Los Angeles County ◽  
Special Health Care Needs ◽  
Health Care Needs ◽  
Care Needs ◽  
Special Health Care ◽  
The Relationship ◽  
Special Health

The current study assesses the relationship between continuing education (CE) with a focus on pediatrics and children with special heath care needs and how CE influences the knowledge and comfort levels of prehospital providers who treat these cases. Data are survey responses provided by paramedic and emergency medical technician (EMT) level providers (N = 575) in Los Angeles County. Regression models assessed the relationship between pediatric-focused continuing education and EMTs’ knowledge of and comfort with pediatric cases, adjusting for relevant covariates. EMTs’ participation in continuing education focusing on pediatrics and special health care needs was significantly associated with an increase in perceived comfort and knowledge. Among EMTs who did not receive continuing education focused on either pediatrics or special health care needs, the most frequently reported barrier to education was a perceived lack of availability. The impact of continuing education on perceived comfort and knowledge was more pronounced than the effect of prior experience, especially considering the limited prevalence of provider exposure to pediatric and childhood special health care needs cases compared to adult cases. Expanding educational opportunities is a promising approach to increasing the comfort and knowledge of EMTs who transport and care for pediatric cases.

scholarly journals Review of the relationship between aggregates geology and Los Angeles and micro-Deval tests

2021 ◽  
Vol 80 (3) ◽  
pp. 1963-1980
Author(s):  
Solomon Adomako ◽  
Christian John Engelsen ◽  
Rein Terje Thorstensen ◽  
Diego Maria Barbieri
Keyword(s):  
Los Angeles ◽  
Crystal Size ◽  
Grain Shape ◽  
Mechanical Performance ◽  
Pore Space ◽  
Construction Material ◽  
Engineering Properties ◽  
Coarse Grained ◽  
The Impact ◽  
The Relationship

AbstractRock aggregates constitute the enormous volume of inert construction material used around the globe. The petrologic description as igneous, sedimentary, and metamorphic types establishes the intrinsic formation pattern of the parent rock. The engineering properties of these rocks vary due to the differences in the transformation process (e.g. hydrothermal deposits) and weathering effect. The two most common mechanical tests used to investigate the performance of aggregates are the Los Angeles (LA) and micro-Deval (MD) tests. This study reviewed the geological parameters (including mineralogy, grain and crystal size, grain shape, and porosity) and the relationship to Los Angeles and micro-Deval tests. It was found that high content of primary minerals in rocks (e.g. quartz and feldspar) is a significant parameter for performance evaluation. Traces of secondary and accessory minerals also affect the performance of rocks, although in many cases it is based on the percentage. Furthermore, some studies showed that the effect of mineralogic composition on mechanical strength is not sufficient to draw final conclusions of mechanical performance; therefore, the impact of other textural characteristics should be considered. The disposition of grain size and crystal size (e.g. as result of lithification) showed that rocks composed of fine-grain textural composition of ≤ 1 mm enhanced fragmentation and wear resistance than medium and coarse grained (≥ 1 mm). The effect of grain shape was based on convex and concave shapes and flat and elongated apexes of tested samples. The equidimensional form descriptor of rocks somehow improved resistance to impact from LA than highly flat and elongated particles. Lastly, the distribution of pore space investigated by means of the saturation method mostly showed moderate (R = 0.50) to strong (R = 0.90) and positive correlations to LA and MD tests.

scholarly journals Investigating the Relationship Between Emotion Recognition Software and Usability Metrics

i-com ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 139-151
Author(s):  
Thomas Schmidt ◽  
Miriam Schlindwein ◽  
Katharina Lichtner ◽  
Christian Wolff
Keyword(s):  
Emotion Recognition ◽  
Regression Models ◽  
Affective Computing ◽  
Large Scale ◽  
General Purpose ◽  
Thinking Aloud ◽  
Continue Research ◽  
Usability Metrics ◽  
Recognition Software ◽  
The Relationship

AbstractDue to progress in affective computing, various forms of general purpose sentiment/emotion recognition software have become available. However, the application of such tools in usability engineering (UE) for measuring the emotional state of participants is rarely employed. We investigate if the application of sentiment/emotion recognition software is beneficial for gathering objective and intuitive data that can predict usability similar to traditional usability metrics. We present the results of a UE project examining this question for the three modalities text, speech and face. We perform a large scale usability test (N = 125) with a counterbalanced within-subject design with two websites of varying usability. We have identified a weak but significant correlation between text-based sentiment analysis on the text acquired via thinking aloud and SUS scores as well as a weak positive correlation between the proportion of neutrality in users’ voice and SUS scores. However, for the majority of the output of emotion recognition software, we could not find any significant results. Emotion metrics could not be used to successfully differentiate between two websites of varying usability. Regression models, either unimodal or multimodal could not predict usability metrics. We discuss reasons for these results and how to continue research with more sophisticated methods.

Food Insecurity Partially Mediates the Association Between Drug Use and Depressive Symptoms among Men who have Sex with Men in Los Angeles, California

2021 ◽  
pp. 1-26
Author(s):  
David A. Wiss ◽  
Marjan Javanbakht ◽  
Michael J. Li ◽  
Michael Prelip ◽  
Robert Bolan ◽  
...  
Keyword(s):  
Food Security ◽  
Depressive Symptoms ◽  
High Risk ◽  
Los Angeles ◽  
Drug Use ◽  
Food Insecurity ◽  
Hiv Positive ◽  
Sex With Men ◽  
The Relationship ◽  
Hiv Negative

Abstract Objective: To understand the relationship between drug use, food insecurity (FI), and mental health among men who have sex with men (MSM). Design: Cohort study (2014-2019) with at least one follow-up. Setting: Visits at 6-month intervals included self-assessment for FI and depressive symptoms. Urine testing results confirmed drug use. Factors associated with FI were assessed using multiple logistic regression with random effects for repeated measures. General structural equation modeling tested whether FI mediates the relationship between drug use and depressive symptoms. Participants: Data were from HIV-positive and high-risk HIV negative MSM in Los Angeles, CA (n=431; 1,192 visits). Results: At baseline, FI was reported by 50.8% of participants, depressive symptoms in 36.7%, and 52.7% of urine screening tests were positive for drugs (i.e., marijuana, opioids, methamphetamine, cocaine, ecstasy). A positive drug test was associated with a 96% increase in the odds of being food insecure (95% CI: 1.26-3.07). Compared to those with high food security, individuals with very low food security have a nearly 7-fold increase in the odds of reporting depressive symptoms (95% CI: 3.71-11.92). Findings showed 14.9% of the association between drug use (exposure) and depressive symptoms (outcome) can be explained by FI (mediator). Conclusion: The prevalence of FI among this cohort of HIV-positive and high-risk HIV-negative MSM was high; the association between drug use and depressive symptoms was partially mediated by FI. Findings suggest that enhancing access to food and nutrition may improve mood in the context of drug use, especially among MSM at risk for HIV-transmission.

scholarly journals A Novel Approach for Operating Speed Continuous Predication Based on Alignment Space Comprehensive Index

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ying Yan ◽  
Gengping Li ◽  
Jinjun Tang ◽  
Zhongyin Guo
Keyword(s):  
Field Experiments ◽  
Prediction Models ◽  
Three Dimensional ◽  
Safety Evaluation ◽  
Driving Safety ◽  
Operating Speed ◽  
Passenger Cars ◽  
Comprehensive Index ◽  
Novel Approach ◽  
Lane Width

Operating speed is a critical indicator for road alignment consistency design and safety evaluation. Although extensive studies have been conducted on operating speed prediction, few models can finish practical continuous prediction at each point along alignment on multilane highways. This study proposes a novel method to estimate the operating speed for multilane highways in China from the aspect of the three-dimensional alignment combination. Operating speed data collected in field experiments on 304 different alignment combination sections are detected by means of Global Positioning System. First, the alignment comprehensive index (ACI) is designed and introduced to describe the function accounting for alignment continuity and driving safety. The variables used in ACI include horizontal curve radius, change rate of curvature, deflection angle of curve, grade, and lane width. Second, the influence range of front and rear alignment on speed is determined on the basis of drivers’ fixation range and dynamical properties of vehicles. Furthermore, a prediction model based on exponential relationships between road alignment and speeds is designed to predict the speed of passenger cars and trucks. Finally, three common criteria are utilized to evaluate the effectiveness of the prediction models. The results indicate that the prediction models outperform the other two operating speed models for their higher prediction accuracy.

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