165 research outputs found

    Effects of Transit Signal Priority on Traffic Safety: Interrupted Time Series Analysis of Portland, Oregon, Implementations

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    Transit signal priority (TSP) has been implemented to transit systems in many cities of the United States. In evaluating TSP systems, more attention has been given to its operational effects than to its safety effects. Existing studies assessing safety effects of TSP reported mixed results, indicating that the safety effects of TSP vary in different contexts. In this study, TSP implementations in Portland, Oregon, were assessed using interrupted time series analysis (ITSA) on month-to-month changes in number of crashes from January 1995 to December 2010. Single-group and controlled ITSA were conducted for all crashes, property-damage-only crashes, fatal and injury crashes, pedestrian-involved crashes, and bike-involved crashes. Evaluation of the post-intervention period (2003 to 2010) showed a reduction in all crashes on street sections with TSP (-4.5 percent), comparing with the counterfactual estimations based on the control group data. The reduction in property-damage-only crashes (-10.0 percent) contributed the most to the overall reduction. Fatal and injury crashes leveled out after TSP implementation but did not change significantly comparing with the control group. Pedestrian and bike-involved crashes were found to increase in the post-intervention period with TSP, comparing with the control group. Potential reasons to these TSP effects on traffic safety were discussed.Comment: Published in Accident Analysis & Preventio

    Real-time Traveler Information Performance Measures for Work Zone Congestion Management

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    To mitigate the work zone impacts on freeways, an advanced traveler information system (ATIS) was designed to promote the utilization of alternative routes and improve local road network performance. The system evaluation was performed during a bridge reconstruction project on the four-lane divided I-39/90 near the interchange with WIS59 at Edgerton, Wisconsin. Field comparisons between ATIS presence and absence discovered different diversion patterns in northbound and southbound directions associated with traffic delay. Drivers remained on the freeway when the displayed delay was less than 15 minutes while more drivers chose to leave the freeway with displayed delay greater than or equal to 15 minutes. A linear regression analysis was further conducted to investigate the impact of several factors, such as displayed delay time, freeway volume, exiting volume during the normal days (without a work zone), and the number of days after system implementation, on driver’s diversion behavior. The results showed that freeway volume, ramp exiting volume during normal days, and delay time were significant variables in causing a high diversion rate.In addition, it was demonstrated that ATIS performed effectively in increasing the work zone operational capacity. Furthermore, the reduced operating speed associated with the advance speed warning (part of the system) suggested that drivers reacted to the warning messages responding to the real-time speed collected through detectors. This comprehensive evaluation enriched the knowledge of driver behavior and reaffirmed the effectiveness of ITS applications in congestion mitigation

    Developing a Conceptual Tribal Crash Safety Dashboard: Data-Driven Strategies for Identifying High-Risk Areas and Enhancing Tribal Safety Programs

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    Tribal lands in the United States have consistently exhibited higher crash rates and injury severities compared to other regions. To address this issue, effective data-driven safety analysis methods are essential for resource allocation and tribal safety program development. This study outlines the minimum data requirements and presents a generic tribal crash dashboard prototype to enable feasible and reproducible tribal crash analysis. The dashboard offers statistical performance measurement techniques, tracks tribal safety trends using various indicators, and updates in with incoming data, making it adaptable for any state. Specifically, the dashboard's capabilities are showcased using Wisconsin tribal crash data, locating high-risk tribal land areas while analyzing and comparing statewide crashes and tribal crashes based on severity. The results reveal that tribal land roads, particularly rural ones, are more dangerous than those in other Wisconsin areas. The dashboard also examines crash types to uncover the causes and insights behind Wisconsin tribal crashes. Demonstrating this dashboard concept reveals its potential to facilitate a more intuitive understanding of tribal crashes from a statistical standpoint, thereby enabling more effective applications of available data sources and the development of targeted safety countermeasures

    Incorporating safety into targeted pavement friction data collection and maintenance procedures

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    The objective of this research was to develop a methodology for targeted pavement friction data collection based on the analysis of weather-related crashes. Furthermore, the aim was to identify threshold values of pavement friction characteristics indicating a significant impact on safety prompting the need for maintenance and improvements. Spatial analysis using Local Moran’s I statistic identified hotspots where pavement friction data were collected. A master database was assembled including Wisconsin State Trunk Network (STN) road attributes, hotspots of weather-related crashes, and pavement friction data collected based on hotspot analysis. The analysis results provide evidence in support of hotspot analysis as a viable procedure for targeted pavement friction data collection to enable efficiency and cost reductions. Classification tree analysis using GUIDE (Generalized, Unbiased, Interaction Detection and Estimation) algorithm was used to further explore the relationship between pavement friction characteristics and safety. Statistically significant hotspots were observed below a pavement friction number of approximately 57 and very high hotspots below a pavement friction number of approximately 42. The results indicate that pavement friction thresholds identified in the literature between 20 and 32 may be too low and that safety may be impacted at friction numbers as high as in the forties. The results also show differences in friction and safety for various types of pavement surfaces. The use of weather-related crashes provides a data-driven and cost-effective method of prioritizing locations for pavement friction data collection and maintenance. Results from this research can be readily used in initial steps of systemic road safety management procedures by practitioners

    Evaluating Lipid-Lowering Drug Targets for Parkinson's Disease Prevention with Mendelian Randomization

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    Long-term exposure to lipid-lowering drugs might affect Parkinson's disease (PD) risk. We conducted Mendelian randomization analyses where genetic variants indexed expected effects of modulating lipid-lowering drug targets on PD. Statin exposure was not predicted to increase PD risk, although results were not precise enough to support benefits for prevention clearly (odds ratio [OR] = 0.83; 95% confidence interval [CI] = 0.65, 1.07). Other target results were null, except for variants indicating Apolipoprotein-A5 or Apolipoprotein-C3 inhibition might confer protection. These findings suggest peripheral lipid variation may not have a prominent role in PD etiology, but some related drug targets could influence PD via alternate pathways. ANN NEUROL 2020;88:1043–104

    Sustainability effects of next-generation intersection control for autonomous vehicles

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    Transportation sustainability is adversely affected by recurring traffic congestions, especially at urban intersections. Frequent vehicle deceleration and acceleration caused by stop-and-go behaviours at intersections due to congestion adversely impacts energy consumption and ambient air quality. Availability of the maturing vehicle technologies such as autonomous vehicles and Vehicle-To-Vehicle (V2V) / Vehicle-To-Infrastructure (V2I) communications provides technical feasibility to develop solutions that can reduce vehicle stops at intersections, hence enhance the sustainability of intersections. This paper presents a next-generation intersection control system for autonomous vehicles, which is named ACUTA. ACUTA employs an enhanced reservation-based control algorithm that controls autonomous vehicles’ passing sequence at an intersection. Particularly, the intersection is divided into n-by-n tiles. An intersection controller reserves certain time-space for each vehicle, and assures no conflict exists between reservations. The algorithm was modelled in microscopic traffic simulation platform VISSIM. ACUTA algorithm modelling as well as enhancement strategies to minimize vehicle intersection stops and eventually emission and energy consumption were discussed in the paper. Sustainability benefits offered by this next-generation intersection were evaluated and compared with traditional intersection control strategies. The evaluation reveals that multi-tile ACUTA reduces carbon monoxide (CO) and Particulate Matter (PM) 2.5 emissions by about 5% under low to moderate volume conditions and by about 3% under high volume condition. Meanwhile, energy consumption is reduced by about 4% under low to moderate volume conditions and by about 12% under high volume condition. Compared with four-way stop control, single-tile ACUTA reduces CO and PM 2.5 emissions as well as energy consumption by about 15% under any prevailing volume conditions. These findings validated the sustainability benefits of employing next-generation vehicle technologies in intersection traffic control. In addition, extending the ACUTA to corridor level was explored in the paper

    Evaluation of Winter Maintenance with Salt Brine Applications in Wisconsin

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    Salt has been traditionally used in winter roadway maintenance. Due to driver expectations and level of service, use of salt and cost have significantly increased over the years. Transportation agencies have been introducing responsible and sustainable winter maintenance practices to alleviate impacts on the environment, human health, vehicles, infrastructure, and reduce costs. Salt brine has been implemented in Wisconsin for several years and there is a need to evaluate its performance. Previous research indicated that there may be a significant reduction of salt and time to bare/wet when using salt brine compared to solid salt in Wisconsin. In this research project, data collection and analysis were expanded from previous research efforts to evaluate salt brine performance in terms of amount of salt used, time to bare/wet, pavement friction, and benefit-cost. The methodology consisted of route selection, route and equipment data collection, winter storm event field data collection (weather, material, application rates, and performance), pavement friction data collection, and data analysis (comparison between study and control routes). Field data were collected from 10 counties (Brown, Dane, Jefferson, Marathon, Marquette, Outagamie, Price, Shawano, Washington, and Wood) in Wisconsin and there were 143 storms evaluated during the 2020-2021 winter season. Field data were collected from study and control routes at the same time and under the same weather conditions. Pavement friction data were collected from two counties (Jefferson and Wood). Key findings of this research indicate that salt brine applications reduced the amount of salt used, improved time to bare/wet, presented better pavement friction conditions, and benefits outweighed the cost of investment to introduce salt brine to existing solid salt applications

    The domestication of SARS-CoV-2 into a seasonal infection by viral variants

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    IntroductionThe COVID-19 pandemic was caused by the zoonotic betacoronavirus SARS-CoV-2. SARS-CoV-2 variants have emerged due to adaptation in humans, shifting SARS-CoV-2 towards an endemic seasonal virus. We have termed this process ‘virus domestication’.MethodsWe analyzed aggregate COVID-19 data from a publicly funded healthcare system in Canada from March 7, 2020 to November 21, 2022. We graphed surrogate calculations of COVID-19 disease severity and SARS-CoV-2 variant plaque sizes in tissue culture.Results and DiscussionMutations in SARS-CoV-2 adapt the virus to better infect humans and evade the host immune response, resulting in the emergence of variants with altered pathogenicity. We observed a decrease in COVID-19 disease severity surrogates after the arrival of the Delta variant, coinciding with significantly smaller plaque sizes. Overall, we suggest that SARS-CoV-2 has become more infectious and less virulent through viral domestication. Our findings highlight the importance of SARS-CoV-2 vaccination and help inform public policy on the highest probability outcomes during viral pandemics

    Motorcycle Licensing and Safety

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    0092-15-11All Wisconsin residents who plan to operate a Type 1 motorcycle on public roads must have a Class M (Motorcycle) license. In 2012, more than 513,000 Wisconsin residents held a valid Class M License. Data indicates there could be as many as 31,000 unlicensed motorcycle operators in the state without a Class M endorsement. Unlicensed operators account for approximately 35% of motorcycle fatalities, and there is concern that unlicensed operators may not be operating as safely as licensed operators. One component of this study was to gather data on the true safety differences between licensed and unlicensed motorcycle operators. In addition to quantifying the numbers of both operators, this study examines crash data to determine differences in riding habits. The Wisconsin Department of Transportation (WisDOT) conducted an initiative to encourage Wisconsin motorcyclists who own registered motorcycles and who are likely riding without appropriate Class M Licensing to successfully complete some form of formal rider education to become compliant under Wisconsin law. To increase compliance and provide outreach to the community, WisDOT needs to have accurate information on how many of these owners do not have a Class M license and their contact information; the safety differences between licensed and unlicensed operators; an analysis of crash data to determine driving habits of unlicensed riders; and an understanding of the major barriers to obtaining licenses
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