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(1 - 7 of 7)
- Title
- RIGHT TURN SPLIT: A NEW DESIGN TO ALLEVIATE WEAVING ON ARTERIAL STREETS.
- Creator
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Shaaban, Khaled, Radwan, Essam, University of Central Florida
- Abstract / Description
-
While weaving maneuvers occur on every type of roadway, most studies have focused on freeway maneuvers. Weaving occurring on non-freeway facilities, such as arterial streets, can cause significant operational problems. Arterial streets weaving typically occur when vehicles coming from a side street at an upstream intersection attempt to enter the main street from one side to reach access points on the opposite site at a downstream intersection by crossing one or more lanes. This dissertation...
Show moreWhile weaving maneuvers occur on every type of roadway, most studies have focused on freeway maneuvers. Weaving occurring on non-freeway facilities, such as arterial streets, can cause significant operational problems. Arterial streets weaving typically occur when vehicles coming from a side street at an upstream intersection attempt to enter the main street from one side to reach access points on the opposite site at a downstream intersection by crossing one or more lanes. This dissertation investigates the type of problems occurring on arterial streets due to the weaving movements and recommends a new design to alleviate weaving on arterial streets. Firstly, the dissertation examined the different weaving movements occurring between two close-spaced intersections at two sites in Florida and explained the breakdown conditions caused by the weaving movements at the two sites. Secondly, the dissertation proposed a new design, Right Turn Split (RTS), to alleviate the delay caused by the weaving movements. The new design proposed separating the worst weaving movement entering the arterial from the other movements and providing a separate path for this movement. The new method is easy to implement and does not require much right of way. Thirdly, the dissertation compared two microscopic models, SimTraffic and VISSIM, to choose the most suitable model to be used to study the operational benefits of the RTS design. Based on the results of the comparison, it was decided to use SimTraffic for the analysis. Fourthly, the dissertation proposed a new calibration and validation procedure for microscopic simulation models. The procedure was applied on SimTraffic using the traffic data from the two studied sites. The proposed procedure appeared to be properly calibrating and validating the SimTraffic simulation model. Finally, the calibrated and validated model was used to study the operational benefits of the RTS design. Using a wide range of geometric and volume conditions, 729 before and after pairs were created to compare the delay of similar scenarios before and after applying the RTS design. The results were analyzed graphically and statistically. The findings of the analysis showed that the RTS design provided lower delay on the arterial street than the original conditions.
Show less - Date Issued
- 2005
- Identifier
- CFE0000402, ucf:46346
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000402
- Title
- SEVERITY ANALYSIS OF DRIVER CRASH INVOLVEMENTS ON MULTILANE HIGH SPEED ARTERIAL CORRIDORS.
- Creator
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Nevarez-Pagan, Alexis, Abdel-Aty, Mohamed, University of Central Florida
- Abstract / Description
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Arterial roads constitute the majority of the centerline miles of the Florida State Highway System. Severe injury involvements on these roads account for a quarter of the total severe injuries reported statewide. This research focuses on driver injury severity analysis of statewide multilane high speed arterials using crash data for the years 2002 to 2004. The first goal is to test different ways of analyzing crash data (by road entity and crash types) and find the best method of driver...
Show moreArterial roads constitute the majority of the centerline miles of the Florida State Highway System. Severe injury involvements on these roads account for a quarter of the total severe injuries reported statewide. This research focuses on driver injury severity analysis of statewide multilane high speed arterials using crash data for the years 2002 to 2004. The first goal is to test different ways of analyzing crash data (by road entity and crash types) and find the best method of driver injury severity analysis. A second goal is to find driver, vehicle, road and environment related factors that contribute to severe involvements on multilane arterials. Exploratory analysis using one year of crash data (2004) using binary logit regression was used to measure the risk of driver severe injury given that a crash occurs. A preliminary list of significant factors was obtained. A massive data preparation effort was undertaken and a random sample of multivehicle crashes was selected for final analysis. The final injury severity analysis consisted of six road entity models and twenty crash type models. The data preparation and sampling was successful in allowing a robust dataset. The overall model was a good candidate for the analysis of driver injury severity on multilane high speed roads. Driver injury severity resulting from angle and left turn crashes were best modeled by separate non-signalized intersection crash analysis. Injury severity from rear end and fixed object crashes was best modeled by combined analysis of pure segment and non-signalized intersection crashes. The most important contributing factors found in the overall analysis included driver related variables such as age, gender, seat belt use, at-fault driver, physical defects and speeding. Crash and vehicle related contributing factors included driver ejection, collision type (harmful event), contributing cause, type of vehicle and off roadway crash. Multivehicle crashes and interactions with intersection and off road crashes were also significant. The most significant roadway related variables included speed limit, ADT per lane, access class, lane width, roadway curve, sidewalk width, non-high mast lighting density, type of friction course and skid resistance. The overall model had a very good fit but some misspecification symptoms appeared due to major differences in road entities and crash types by land use. Two additional models of crashes for urban and rural areas were successfully developed. The land use models' goodness of fit was substantially better than any other combination by road entity or the overall model. Their coefficients were substantially robust and their values agreed with scientific or empirical principles. Additional research is needed to prove these results for crash type models found most reliable by this investigation. A framework for injury severity analysis and safety improvement guidelines based on the results is presented. Additional integration of road characteristics (especially intersection) data is recommended for future research. Also, the use of statistical methods that account for correlation among crashes and locations are suggested for use in future research.
Show less - Date Issued
- 2008
- Identifier
- CFE0002080, ucf:47591
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002080
- Title
- Brief Behavioral Health Intervention Program for Patients with Stable Coronary Artery Disease.
- Creator
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Wiener, Chelsea, Cassisi, Jeffrey, Gupta, Rema, Paulson, Daniel, University of Central Florida
- Abstract / Description
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Healthy eating, physical activity, stress management, and smoking cessation are widely recognized as essential for preventing and treating coronary artery disease (CAD). Research on lifestyle programs for patients with CAD has largely focused on long-term interventions (e.g., several months to one-year in duration). Further, many studies have recruited patients immediately post-cardiac event. By contrast, evaluation of brief lifestyle interventions for stable patients treated in outpatient...
Show moreHealthy eating, physical activity, stress management, and smoking cessation are widely recognized as essential for preventing and treating coronary artery disease (CAD). Research on lifestyle programs for patients with CAD has largely focused on long-term interventions (e.g., several months to one-year in duration). Further, many studies have recruited patients immediately post-cardiac event. By contrast, evaluation of brief lifestyle interventions for stable patients treated in outpatient cardiology is lacking. The present study evaluated the feasibility, acceptability, and efficacy of a 3-session behavioral health lifestyle program for patients with stable CAD being treated in an outpatient cardiology clinic. Thirty-three patients were randomized to the Intervention Group (IG) or to Treatment as Usual (TAU). Outcome measures were assessed at Post-treatment (two-weeks after Baseline) and at 30-day Follow-up. Reliable change and parametric analyses were used to evaluate study outcomes. Results indicated that the program was both feasible and acceptable to patients, as determined by a priori criteria: over 60 percent of referred and eligible patients agreed to participate, over 75 percent of consented IG participants completed the program through 30-day Follow-up, and over 80 percent of participants reported that they would recommend the program to other patients. With regard to treatment outcomes, data from 28 participants were available. Reliable change analyses revealed that at both Post-treatment and 30-day Follow-up, significantly more IG than TAU participants exhibited an increase in self-efficacy as compared with Baseline. There were no observed between-group differences on other study measures, though repeated-measures ANOVAs were underpowered. Overall, results support the feasibility and acceptability of brief lifestyle interventions in outpatient cardiology care and highlight the role of behavioral health providers on integrated cardiology care teams in helping to increase patient self-efficacy in managing chronic disease.
Show less - Date Issued
- 2019
- Identifier
- CFE0007876, ucf:52770
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007876
- Title
- SAFETY IMPROVEMENTS ON MULTILANE ARTERIALS A BEFORE AND AFTER EVALUATION USING THE EMPIRICAL BAYES METHOD.
- Creator
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Devarasetty, Prem Chand, Abdel-Aty, Mohamed, University of Central Florida
- Abstract / Description
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This study examines the safety effects of the improvements made on multi-lane arterials. The improvements were divided into two categories 1) corridor level improvements, and 2) intersection improvements. Empirical Bayes method, which is one of the most accepted approaches for conducting before-after evaluations, has been used to assess the safety effects of the improvement projects. Safety effects are estimated not only in terms of all crashes but also rear-end (most common type) as well as...
Show moreThis study examines the safety effects of the improvements made on multi-lane arterials. The improvements were divided into two categories 1) corridor level improvements, and 2) intersection improvements. Empirical Bayes method, which is one of the most accepted approaches for conducting before-after evaluations, has been used to assess the safety effects of the improvement projects. Safety effects are estimated not only in terms of all crashes but also rear-end (most common type) as well as severe crashes (crashes involving incapacitating and/or fatal injuries) and also angle crashes for intersection improvements. The Safety Performance Functions (SPFs) used in this study are negative binomial crash frequency estimation models that use the information on ADT, length of the segments, speed limit, and number of lanes for corridors. And for intersections the explanatory variables used are ADT, number of lanes, speed limit on major road, and number of lanes on the minor road. GENMOD procedure in SAS was used to develop the SPFs. Corridor SPFs are segregated by crash groups (all, rear-end, and severe), length of the segments being evaluated, and land use (urban, suburban and rural). The results of the analysis show that the resulting changes in safety following corridor level improvements vary widely. Although the safety effect of projects involving the same type of improvement varied, the overall effectiveness of each of the corridor level improvements were found to be positive in terms of reduction in crashes of each crash type considered (total, severe, and rear-end) except for resurfacing projects where the total number of crashes slightly increased after the roadway section is resurfaced. Evaluating additional improvements carried out with resurfacing activities showed that all (other than sidewalk improvements for total crashes) of them consistently led to improvements in safety of multilane arterial sections. It leads to the inference that it may be a good idea to take up additional improvements if it is cost effective to do them along with resurfacing. It was also found that the addition of turning lanes (left and/or right) and paving shoulders were two improvements associated with a project's relative performance in terms of reduction in rear-end crashes. No improvements were found to be associated with a resurfacing project's relative performance in terms of changes in (i.e., reducing) severe crashes. For intersection improvements also the individual results of each project varied widely. Except for adding turn lane(s) all other improvements showed a positive impact on safety in terms of reducing the number of crashes for all the crash types (total, severe, angle, and rear-end) considered. Indicating that the design guidelines for this work type have to be revisited and safety aspect has to be considered while implementing them. In all it can be concluded that FDOT is doing a good job in selecting the sites for treatment and it is very successful in improving the safety of the sections being treated although the main objective(s) of the treatments are not necessarily safety related.
Show less - Date Issued
- 2009
- Identifier
- CFE0002723, ucf:48148
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002723
- Title
- Prehabilitation (Prehab): Prevention in Motion.
- Creator
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Russell, Billie, Sole, Mary Lou, Chase, Susan, Damato-Kubiet, Leslee, Gammonley, Denise, University of Central Florida
- Abstract / Description
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ABSTRACTCardiovascular disease is the leading cause of death for U.S. adults. It adds greater than $100 billion to U.S. health care costs annually. Rates of morbidity, mortality, and economic burden of the disease could be dramatically reduced with improvements in sedentary behaviors among adults with coronary artery disease (CAD). A regular commitment to moderate physical activity can reduce ischemic heart events up to 50%. Although the benefits of physical activity are well-known for...
Show moreABSTRACTCardiovascular disease is the leading cause of death for U.S. adults. It adds greater than $100 billion to U.S. health care costs annually. Rates of morbidity, mortality, and economic burden of the disease could be dramatically reduced with improvements in sedentary behaviors among adults with coronary artery disease (CAD). A regular commitment to moderate physical activity can reduce ischemic heart events up to 50%. Although the benefits of physical activity are well-known for individuals with coronary artery disease, an estimated 70% of this population remains relatively sedentary. Hospital-based cardiac rehabilitation programs are the single secondary prevention option offered to improve physical activity habits in persons with CAD. Although effective, cardiac rehabilitation is inaccessible for the majority of CAD sufferers and is offered only after an acute cardiac event. Different from rehabilitation, prehabilitation (prehab) programs use physical activity as a means to deter a worsening condition or prevent injury before an acute event occurs. These programs have proved successful in other areas of medicine but there are currently no such secondary prevention programs available for stable persons with CAD in the U.S. A home-based prehab program could help adults with CAD establish improved physical activity habits and circumvent many of the barriers associated with admission and attendance of a hospital-based cardiac rehabilitation program. Researchers have indicated that self-efficacy is key to initiation and sustentation of a regular physical activity habit, regardless of the physical activity program that one attends. These habits are more likely to last when participants receive self-efficacy based support for an average of 66 days. The purpose of this study was to determine if a nurse-practitioner-led, home-based, prehab program could assist adults with CAD to improve and maintain increased physical activity habits and levels of self-efficacy for physical activity. The five primary facilitators of self-efficacy were used to devise a 10-week prehab program. A convenience sample of 54 adults with diagnosed CAD was recruited from cardiology practices in St. Johns County, Florida. The research population was 68.5% (n=37) male, 88.9% (n=48) Caucasian, and 74% (n=40) married with a mean age of 68.57 years. Participants attended a 90-minute prehab class which offered health education and group discussion of barriers and goals for regular physical activity. Following the class, participants were contacted weekly for 10-weeks to discuss goal progress, assist in circumventing barriers, and revise physical activity goals as needed. After the 10-week call period, participants were contacted 30-days later to assess for physical activity habit maintenance and any sustained benefit in self-efficacy for physical activity. Self-efficacy for exercise was measured before the prehab class, after the prehab class, and after the 10-week intervention period using the Short Self-Efficacy Expectations scale (SSEE), Multidimensional Outcomes Expectations for Exercise Scale (MOEES), and the Barriers Self-Efficacy Scale (BARSE). All baseline measures of self-efficacy (MOEES, BARSE, SSEE) improved significantly immediately following the prehab class. Baseline physical outcome expectations of the MOEES (m=21.87, sd=4.67), self-evaluative outcome expectations of the MOEES (m=16.70, sd=4.15) and SSEE (m=12.75, sd=4.02) remained significantly improved after the 10-week intervention period (p(<).05). At the 10-week assessment, mean significant self-efficacy scores were 24.39 (sd=1.26, p(<).01) for physical outcome expectations, 18.39 (sd=2.27, p(<).02) for self-evaluative outcome expectations, and 15.06, (sd=3.25, p(<).001) for SSEE. The SSEE was reassessed 30-days after the study and remained significantly improved compared to baseline (m=15.65, sd=3.42, p(<).01). Qualitative data collection coincided with the quantitative self-efficacy findings. Participants reported satisfaction with physical activity goal attainment and increased confidence to continue with a regular physical activity plan. The Godin Leisure-Time Exercise Questionnaire (GLTEQ) was used to assess activity levels at baseline, during each weekly phone call, at the end of 10-weeks, and 30-days after the study. Repeated-measures ANOVA (F (2,90) = 21.86, p(<).001) revealed that participant's baseline physical activity volume measured by GLTEQ (m=18.39, sd= 16.93) improved significantly after 10 weeks in the prehab study (m=41.10, sd=24.11, p(<).001) and remained significantly improved when re-measured 30-days after the study (m=39.02, sd=21.87, p(<).001). Qualitative data concurred with quantitative data with participants reporting physical activity habit formation and maintenance of self-regulatory skills. Qualitative data also demonstrated that participants in prehab experienced very similar facilitators and barriers compared to other adults with CAD attempting an exercise program. In summary, the prehab study findings coincided with other research findings in this area. Self-efficacy based support can assist individuals with CAD to improve and maintain physical activity habits. The ease of the intervention likely contributed to lower cost and attrition rates (7%) compared to hospital-based cardiac rehabilitation programs. Although more research is needed, study findings suggest that a nurse-practitioner-led, home-based program could be a viable secondary prevention strategy for stable adults with CAD. This should be considered for the future given that even modest improvements in physical activity can substantially reduce all-cause mortality in this population.
Show less - Date Issued
- 2016
- Identifier
- CFE0006384, ucf:51530
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006384
- Title
- LEVEL-OF-SERVICE AND TRAFFIC SAFETY RELATIONSHIP: AN EXPLORATORY ANALYSIS OF SIGNALIZED INTERSECTIONS AND MULTILANE HIGH-SPEED ARTERIAL CORRIDORS.
- Creator
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Almonte-Valdivia, Ana, Abdel-Aty, Mohamed, University of Central Florida
- Abstract / Description
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Since its inception in 1965, the Level-of-Service (LOS) has proved to be an important and practical "quality of service" indicator for transportation facilities around the world, widely used in the transportation and planning fields. The LOS rates these facilities' traffic operating conditions through the following delay-based indicators (ordered from best to worst conditions): A, B, C, D, E and F. This LOS rating has its foundation on quantifiable measures of effectiveness (MOEs) and on...
Show moreSince its inception in 1965, the Level-of-Service (LOS) has proved to be an important and practical "quality of service" indicator for transportation facilities around the world, widely used in the transportation and planning fields. The LOS rates these facilities' traffic operating conditions through the following delay-based indicators (ordered from best to worst conditions): A, B, C, D, E and F. This LOS rating has its foundation on quantifiable measures of effectiveness (MOEs) and on road users' perceptions; altogether, these measures define a LOS based on acceptable traffic operating conditions for the road user, implying that traffic safety is inherent to this definition. However, since 1994 safety has been excluded from the LOS definition since it cannot be quantified nor explicitly defined. The latter has been the motivation for research based on the LOS-Safety relationship, conducted at the University of Central Florida (UCF). Using data from two of the most studied transportation facility types within the field of traffic safety, signalized intersections and multilane high-speed arterial corridors, the research conducted has the following main objectives: to incorporate the LOS as a parameter in several traffic safety models, to extend the methodology adopted in previous studies to the subject matter, and to provide a platform for future transportation-related research on the LOS-Safety relationship. A meticulous data collection and preparation process was performed for the two LOS-Safety studies comprising this research. Apart from signalized intersections' and multilane-high speed arterial corridors' data, the other required types of information corresponded to crashes and road features, both obtained from FDOT's respective databases. In addition, the Highway Capacity Software (HCS) and the ArcGIS software package were extensively used for the data preparation. The result was a representative and robust dataset for each LOS-Safety study, to be later tested and analyzed with appropriate statistical methods. Regarding the LOS-Safety study for signalized intersections, two statistical techniques were used. The Generalized Estimating Equations (GEEs), the first technique, was used for the analyses considering all periods of a regular weekday (i.e. Monday through Friday): Early Morning, A.M. Peak, Midday, P.M. Peak and Late Evening; the second technique considered was the Negative Binomial, which was used for performing an individual analysis per period of the day. On the other hand, the LOS-Safety study for multilane high-speed arterial corridors made exclusive use of the Negative Binomial technique. An appropriate variable selection process was required for the respective model building and calibration procedures; the resulting models were built upon the six following response variables: total crashes, severe crashes, as well as rear-end, sideswipe, head-on and angle plus left-turn crashes. The final results proved to be meaningful for the understanding of traffic congestion effects on road safety, and on how they could be useful within the transportation planning scope. Overall, it was found that the risk for crash occurrence at signalized intersections and multilane high-speed arterial corridors is quite high between stable and unacceptable operating conditions; it was also found that this risk increases as it becomes later in the day. Among the significant factors within the signalized intersection-related models were LOS for the intersection as a whole, cycle length, lighting conditions, land use, traffic volume (major and minor roads), left-turn traffic volume (major road only), posted speed limit (major and minor roads), total number of through lanes (major and minor roads), overall total and total number of left-turn lanes (major road only), as well as county and period of the day (dummy variables). For multilane-high speed arterial corridors, the final models included LOS for the road section, average daily traffic (ADT), total number of through lanes in a single direction, total length of the road section, pavement surface type, as well as median and inside shoulder widths. A summary of the overall results per study, model implications and each LOS indicator is presented. Some of the final recommendations are to develop models for other crash types, to perform a LOS-Safety analysis at the approach-level for signalized intersections, as well as one that incorporates intersections within the arterial corridors' framework.
Show less - Date Issued
- 2009
- Identifier
- CFE0002615, ucf:48285
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002615
- Title
- Arterial-level real-time safety evaluation in the context of proactive traffic management.
- Creator
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Yuan, Jinghui, Abdel-Aty, Mohamed, Eluru, Naveen, Hasan, Samiul, Cai, Qing, Wang, Liqiang, University of Central Florida
- Abstract / Description
-
In the context of pro-active traffic management, real-time safety evaluation is one of the most important components. Previous studies on real-time safety analysis mainly focused on freeways, seldom on arterials. With the advancement of sensing technologies and smart city initiative, more and more real-time traffic data sources are available on arterials, which enables us to evaluate the real-time crash risk on arterials. However, there exist substantial differences between arterials and...
Show moreIn the context of pro-active traffic management, real-time safety evaluation is one of the most important components. Previous studies on real-time safety analysis mainly focused on freeways, seldom on arterials. With the advancement of sensing technologies and smart city initiative, more and more real-time traffic data sources are available on arterials, which enables us to evaluate the real-time crash risk on arterials. However, there exist substantial differences between arterials and freeways in terms of traffic flow characteristics, data availability, and even crash mechanism. Therefore, this study aims to deeply evaluate the real-time crash risk on arterials from multiple aspects by integrating all kinds of available data sources. First, Bayesian conditional logistic models (BCL) were developed to examine the relationship between crash occurrence on arterial segments and real-time traffic and signal timing characteristics by incorporating the Bluetooth, adaptive signal control, and weather data, which were extracted from four urban arterials in Central Florida. Second, real-time intersection-approach-level crash risk was investigated by considering the effects of real-time traffic, signal timing, and weather characteristics based on 23 signalized intersections in Orange County. Third, a deep learning algorithm for real-time crash risk prediction at signalized intersections was proposed based on Long Short-Term Memory (LSTM) and Synthetic Minority Over-Sampling Technique (SMOTE). Moreover, in-depth cycle-level real-time crash risk at signalized intersections was explored based on high-resolution event-based data (i.e., Automated Traffic Signal Performance Measures (ATSPM)). All the possible real-time cycle-level factors were considered, including traffic volume, signal timing, headway and occupancy, traffic variation between upstream and downstream detectors, shockwave characteristics, and weather conditions. Above all, comprehensive real-time safety evaluation algorithms were developed for arterials, which would be key components for future real-time safety applications (e.g., real-time crash risk prediction and visualization system) in the context of pro-active traffic management.
Show less - Date Issued
- 2019
- Identifier
- CFE0007743, ucf:52398
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007743
