Safety And Operational Evaluation Of Dynamic Lane Merging In Work Zones

Traffic safety and mobility of roadway work zones have been considered to be one of the major concerns in highway traffic safety and operations in Florida. In intent to expose Florida\u27s work zones crash characteristics, the Florida Traffic Crash Records Database for years 2002, 2003 and 2004 were explored. Statistical models were estimated and Florida\u27s work zone crash traits for single vehicle crashes and two-vehicle crashes were drawn. For the single-vehicle crashes, trucks were found more likely to be involved in single vehicle crashes in freeway work zones compared to freeways without work zones. Straight level roadways are significantly affected by the presence of work zones. The lighting condition is also one of the risk factors associated with work zone single-vehicle crashes. In fact, at work areas with poor or no lighting during dark conditions, motor vehicles are more prone for crashes compared to non-work zone locations with poor or no lighting during dark. The weather condition is positively associated with single-vehicle work zone crashes. Results showed that during rainy weather, drivers are less likely to be involved in work zone crashes compared to the same weather conditions in non-work zone locations. This fact may be due to the vigilant driving pattern during rain at work zones. For the two-vehicle work zone crashes, results showed that drivers younger than 25 years of age and drivers older than 75 years old have the highest risk to be the at-fault driver in a work zone crash. Male drivers have significantly higher risk than female drivers to be the at-fault driver. The model conspicuously shows that drivers under the influence of narcotics/alcohol are more likely to cause crashes (i.e. at-fault driver) at work zones. Road geometry and the lighting condition were significant risk factors associated with two-vehicle work zone crashes. Freeways straight segments are more susceptible to crashes in work zone areas. Poor lighting or no lighting at all during dark can lead to significantly higher crash hazard at work zones. Foggy weather causes a significant mount in work zone crash risk compared to non-work zone locations. In addition to that, work zones located in rural areas have higher crash potential than work zones located in urban areas. After examining the current Florida work zone Maintenance of Traffic (MOT) plans, known as the Motorist Awareness System (MAS), it was realized that this system is static hence does not react to changing traffic conditions. An ITS-based dynamic lane management system, known as dynamic lane merging system, was explored to supplement the existing MAS plans. Two forms of dynamic lane management were recognized as dynamic lane merging namely the early merge and the late merge. These two systems were designed to advise drivers on definite merging locations. Previously deployed dynamic lane merging systems comprise several Portable Changeable Message Signs (PCMS) and traffic sensors. The addition of multiple PCMSs to the current MAS plans may encumber the latter and usually requires relatively extensive equipment installation and relocation which could be inefficient for short term movable work zones. Therefore, two Simplified Dynamic Lane Merging Systems (SDLMS) were designed, deployed, and tested on Florida\u27s short term movables work zones. The first SDLMS was a simplified dynamic early merge system (early SDLMS) and the second SDLMS was a simplified dynamic late merge system (late SDLMS). Both SDLMS consisted of supplementing the MAS plans used in Florida work zones with an ITS-based lane management system. From the two-to-one work zone configuration (first site), it was noted that the ratio of the work zone throughput at the onset of congestion over the demand volume was significantly the highest for the early SDLMS compared to the MAS and late SDLMS. Travel time through the work was the lowest for the early SDLMS, followed by the late SDLMS, and then MAS. However, the differences in mean travel times were not statistically significant. It was also concluded that the early SDLMS resulted in higher early merging compared to the MAS and that the late SDLMS in higher late merging compared to the MAS. The first site was used as a pilot for testing the system since data collection was limited to two days for each MOT type. Hence, operational measures of effectiveness (MOEs) could not be evaluated under different demand volumes. It should also be noted that the RTMS was not available during the MAS data collection which disabled us from collecting speed data. From the three-to-two work zone configuration site, data was collected extensively relative to the first site. The RTMS was available for all three MOT types tested which enabled the collection of the speed data that are used as a safety surrogate measure. The mean speed fluctuation in the closed lane was the highest under the MAS system for all demand volumes and in all three lanes. Comparing the dynamic early merge and the dynamic late merge mean speed fluctuations in the closed lane and the middle lane, results showed that the mean speed fluctuation for the early merge are lower than those of the late merge under all demand volumes. However, the difference in the mean speed fluctuation is only statistically significant under demand volume ranging between 1 and 500 veh/hr. As for the shoulder lane, it was noted that the speed mean speed fluctuation is significantly the lowest for demand volumes ranging between 1500 veh/hr and 2000 veh/hr under the late SDLMS compared to the early SDLMS and the MAS. The ratio of the throughput over demand volume was taken as the operational MOE. Results showed that the Dynamic early merge performs significantly better than the regular MAS under demand volume ranging between 500 veh/hr and 2000 veh/hr. Results also showed that the dynamic late merge perform better than the MAS under volumes ranging between 1500 veh/hr and 2000 veh/hr and significantly poorer than the MAS under low volumes. Therefore, the late SDLMS is not recommended for implementation under low volumes. Results also showed that the late SDLMS performs better than the early SDLMS under higher volume (ranging between 1500 veh/hr to 2000 veh/hr). A simulated work zone with a two-to-one lane closure configuration was coded in VISSIM and operational and safety MOEs under MAS, early SDLMS, and late SDLMS were compared under different drivers\u27 adherence rate to the merging instructions, truck percentage in the traffic composition, and traffic demand volumes. Results indicated that throughputs are higher in general under the early SDLMS, travel times are lower under the early SDLMS. However, overall, the early SDLMS resulted in the highest speed variance among MOT types. The MAS resulted in the lowest speed variances overall

Evaluation of New Simplified Dynamic Lane Merging Systems (SDLMS) for Short-Term Work Zone Lane Closure Configuration

To improve traffic safety and mobility in work zone areas, the Dynamic Lane Merge (DLM) systems, intelligent work zone traffic control systems, have been explored by several states of the U.S.A. The DLM can take two forms; dynamic early merge and dynamic late merge. The DLM systems were designed to advise drivers on definite merging locations. Up to date, there are no studies that contrast both merging schemes in the field under matching work zone settings. This study suggests two Simplified Dynamic Lane Merging Systems (SDLMS) (early merge and late merge) to supplement the current Florida Maintenance Of Traffic (MOT) plans for a three-to-two- work zone lane closure configuration. Data was collected in work zones on I-95, Florida for three different maintenance of traffic plan treatments. The first maintenance of traffic plan treatment was the standard MOT plan employed by FDOT. The second MOT was the early SDLMS and the third MOT was the late SDLMS. Results showed that dynamic early merging (early SDLMS) outperforms late SDLMS and the conventional Florida MOT plans under lower demand volumes. However, results also showed that late SDLMS outperforms early SDLMS and MAS under higher demand volumes

The Use Of The Ucf Driving Simiulator To Test The Contribution Of Larger Size Vehicles (lsvs) In Rear-end Collisions And Red Light Running On Intersections.

Driving safety has been an issue of great concern in the United States throughout the years. According to the National Center for Statistics and Analysis (NCSA), in 2003 alone, there were 6,267,000 crashes in the U.S. from which 1,915,000 were injury crashes, including 38,764 fatal crashes and 43,220 human casualties. The U.S. Department of Transportation spends millions of dollars every year on research that aims to improve roadway safety and decrease the number of traffic collisions. In spring 2002, the Center for Advanced Traffic System Simulation (CATSS), at the University of Central Florida, acquired a sophisticated reconfigurable driving simulator. This simulator, which consists of a late model truck cab, or passenger vehicle cab, mounted on a motion base capable of operation with six degrees of freedom, is a great tool for traffic studies. Two applications of the simulator are to study the contribution of Light Truck Vehicles (LTVs) to potential rear-end collisions, the most common type of crashes, which account for about a third of the U.S. traffic crashes, and the involvement of Larger Size Vehicles (LSVs) in red light running. LTVs can obstruct horizontal visibility for the following car driver and has been a major issue, especially at unsignalized intersections. The sudden stop of an LTV, in the shadow of the blindness of the succeeding car driver, may deprive the following vehicle of a sufficient response time, leading to high probability of a rear-end collision. As for LSVs, they can obstruct the vertical visibility of the traffic light for the succeeding car driver on signalized intersection producing a potential red light running for the latter. Two sub-scenarios were developed in the UCF driving simulator for each the vertical and horizontal visibility blockage scenarios. The first sub-scenario is the base sub-scenario for both scenarios, where the simulator car follows a passenger car, and the second sub-scenario is the test sub-scenario, where the simulator car follows an LTV for the horizontal visibility blockage scenario and an LSV for the vertical visibility blockage scenario. A suggested solution for the vertical visibility blockage of the traffic light problem that consisted of adding a traffic signal pole on the right side of the road was also designed in the driving simulator. The results showed that LTVs produce more rear-end collisions at unsignalized intersections due to the horizontal visibility blockage and following car drivers\u27 behavior. The results also showed that LSVs contribute significantly to red light running on signalized intersections and that the addition of a traffic signal pole on the right side of the road reduces the red light running probability

Knowledge, attitudes, beliefs, values, preferences, and feasibility in relation to the use of injection safety devices in healthcare settings: a systematic review

Search strategy used in Medline. (DOC 29 kb

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.