125 research outputs found

    A multiple correspondence analysis of at-fault motorcycle-involved crashes in Alabama

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    According to the U.S. National Highway Traffic Safety Administration, in 2012, more than 4950 motorcyclists were killed in traffic accidents. Compared to passenger car occupants, mile for mile, motorcyclists are more than 26 times more at risk to dying in crashes. Due to the high fatality rate associated with motorcycle crashes, factors contributing to this type of crash must be identified in order to implement effective safety countermeasures. Given that the available datasets are large and complex, identifying the key factors contributing to crashes is a challenging task. Using multiple correspondence analysis, as an exploratory data analysis technique to determine the dataset structure, we identified the roadway/environmental, motorcycle, and motorcyclist‐related variables influencing at‐fault motorcycle‐involved crashes. This study used the latest available dataset (2009 to 2013) from the Critical Analysis Reporting Environment database to study motorcycle crashes in the state of Alabama. The most significant contributors to the frequency and severity of at‐fault motorcycle‐involved crashes were found to be light conditions, time of day, driver condition, and weather conditions

    Long-Term Effectiveness of Radar Speed Display Signs in a University Environment

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    Vehicular speeds are of particular interest in areas with a high number of pedestrians due to the fact that 14-percent of all fatal crashes involve pedestrians. This study investigated the effect of a radar speed display sign placed for an extended period of time, at a location frequented by law enforcement on a road segment entering a university campus with a high number of pedestrians and vehicle speed violations. The statistical analysis included a comparison between AM peak, PM peak, and midday speeds collected one year apart. The data suggested that radar speed display signs can remain effective over a long period of time; causing drivers to decelerate when warned of a speeding violation. While other studies have examined long-term impacts of similar technologies, none have included a road entering a University campus. Thus, these findings support that other similar locations entering university campuses could see long-term benefits to stationary radar speed display signs

    Field Implementation of Direction Rumble Strips for Deterring Wrong-Way Entries

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    This report presents the field implementation results of three directional rumble strip (DRS) patterns designed to deter wrong-way (WW) freeway entries. Southbound off-ramps at Exits 208 and 284 on I-65 in Alabama were selected for implementation because they were ranked as high-risk locations by a network screening tool developed by Auburn University. Three patterns (D3, C, and E.1) were recommended for field implementation based on the results of a previous project. Pattern D3 was installed at the off-ramp terminal near the stop bar or yield line. Pattern C was implemented at the segment between the terminal and ramp curve. Pattern E.1 was placed on the tangent part before the ramp curve. WW incident and traffic speed data before and after the implementation were collected using cameras and magnetic sensors, respectively. Field driving tests were conducted to collect sound and vibration data at various speed categories for both RW and WW directions. Before and after studies evaluated the effectiveness of the DRS patterns in reducing wrong way driving (WWD) incidents and traffic speeds on off-ramps. Sound and vibration analyses quantified the differences between right way (RW) and WW drivers’ perceptions. Results showed that the number of WWD incidents and average driving distances were significantly reduced after implementing all of the DRS. The results confirmed that WWDs can perceive elevated sound and vibrations when passing the DRS. The DRS can also reduce the 85th percentile, mean, and standard deviations of off-ramp traffic speeds. A general guideline was developed for implementing different DRS to deter WW freeway entries

    A Comprehensive Assessment of Highway Inventory Data Collection Methods

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    The implementation of the Highway Safety Manual (HSM) at the state level has the potential to allow transportation agencies to proactively address safety concerns. However, the widespread utilization of HSM faces significant barriers as many state departments of transportations (DOTs) do not have sufficient HSM-required highway inventory data. Many techniques have been utilized by state DOTs and local agencies to collect highway inventory data for other purposes. Nevertheless, it is unknown which of these methods or any combination of them is capable of efficiently collecting the required dataset while minimizing cost and safety concerns. The focus of this study is to characterize the capability of existing methods for collecting highway inventory data vital to the implementation of the recently published HSM. More specifically, this study evaluated existing highway inventory methods through a nationwide survey and a field trial of identified promising highway inventory data collection (HIDC) methods on various types of highway segments. A comparative analysis was conducted to present an example on how to incorporate weights provided by state DOT stakeholders to select the most suitable HIDC method for the specific purpose

    Structural characteristics, antioxidant and hypoglycemic activities of polysaccharides from Mori Fructus based on different extraction methods

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    The mulberry (Mori Fructus), which is rich in many nutrients needed by the human body, serves as both food and medicine. Polysaccharides, which are considered to be important pharmacological components of mulberry, have received a lot of study for their structure and biological activity. In this study, six mulberry fruit polysaccharides (MFPs) were extracted by different extraction methods, and their physicochemical structures, antioxidant, and hypoglycemic biological activities were investigated and compared. According to the findings, MFP-III exhibited the best α-glucosidase and α-amylase inhibition, whereas MFP-IV had the strongest scavenging activity against DPPH and ABTS. Scanner electron microscopy (SEM) and high-performance liquid chromatography (HPLC) analysis showed that the apparent morphology and monosaccharide content of MFP were significantly impacted by the different extraction techniques. The results of experiments using Congo red, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TG), and the Congo red experiment showed that the MFP functional groups, glycosidic bonds, triple helix structure, and thermal stability were not significantly different between the extraction methods. According to the aforementioned research, various extraction methods had different effects on the chemical composition and biological activity of mulberry polysaccharides. This information can provide a scientific basis for selecting suitable extraction methods to obtain mulberry polysaccharides with ideal biological activity

    Establishing Procedures and Guidelines for Pedestrian Treatments at Uncontrolled Locations

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    Pedestrians are the most vulnerable road users. The risks to pedestrians crossing at uncontrolled locations are much higher than at signalized intersections. There has been an increasing trend in pedestrian deaths during the past decade. Specifically, pedestrian fatality as percent of total fatalities indicates an increasing trend in a ten-year period from 2005 to 2014. Several research projects funded by both federal and state transportation agencies have attempted to identify effective strategies for improving pedestrian safety within their jurisdictions. However, very little research was conducted on pedestrian safety at uncontrolled locations in Illinois. The objectives of the project were to identify the best practices of approving pedestrian crossings and pedestrian-crossing treatments at uncontrolled locations and to develop procedures and guidelines to be used by the Illinois Department of Transportation (IDOT) and local agencies. To achieve the research goal, the team conducted a comprehensive literature review of related studies and existing guidelines, a survey and interview of Illinois transportation engineers, statistical analysis of Illinois pedestrian-crash data from 2010 to 2014, and a field review of selected high-crash corridors (HCC) in Illinois. This study identified several common issues associated with the high-pedestrian-crash-prone roads, e.g., speeding, poor lighting, noncompliance with posted signage, inadequate or missing signage, or lack of conspicuity. Several geometric features were also proven to be related to pedestrian crashes; for instance, long crossing distances, insufficient sight distance, and inappropriate placement of bus stops and parking were proved to affect pedestrian safety. In addition, pedestrian-crossing treatments were classified into five categories in the study, and their effectiveness and suitable conditions were assessed and identified. Based on the research findings, a guidebook was compiled with a comprehensive discussion of strategies and treatments to enhance pedestrian safety at uncontrolled locations. The target audiences for this guidebook are transportation professionals, highway designers, traffic engineers, law enforcement officers, and safety specialists who may be involved in efforts to reduce pedestrian crashes at uncontrolled locations.IDOT-R27-167Ope

    Development of Guidance for Unsignalized Intersections on Rural Multilane Divided Highways

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    This research project examines the safety performance of unsignalized intersections on rural divided highways in Alabama. A summary of the safety problem at these intersections is provided; the concern is the relatively high frequency and severity of crashes at these locations, typically associated with vehicles entering from the minor road and failing to successfully cross or turn left onto the second directional roadway. The project objectives included review of the literature, examination of a small set of such intersections in Alabama with innovative treatments, factors that influence safety performance and approaches to estimating performance, and developing design guidance for these locations. During the course of this study, ALDOT developed an Intersection Control Evaluation (ICE) policy, which to some extent addresses the last objective. This study reviewed the literature, estimated calibration factors for safety performance functions for three-leg and four-leg intersections of this type, reviewed geometric and traffic control features that may improve safety performance, and examined differences in safety performance among several selected intersections in Alabama. A review of the literature and current practice found many treatments with respect to geometrics and traffic control devices that can be applied to the conventional form of this type of intersection with the goal of reducing crash frequency and crash severity. An analysis involving 47 three-leg and 65 four-leg intersections in the state yielded recommend calibration factors for the relevant safety performance functions. Several selected sites with atypical design and traffic control treatments were reviewed. Finally, a traffic conflict study across several intersections with conventional and unconventional treatments was conducted to further identify the types of conflicts that contribute to poor safety performance

    Evaluation of Route Diversion Strategies Using Computer Simulation

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