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Browsing by Author "Alden, Andrew"

Now showing 1 - 4 of 4
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    Development and Testing of an Integrated, Versatile, Bicycle-Based Data Acquisition System
    Owens, Justin M.; Alden, Andrew; Antin, Jonathan F.; Gibbons, Ronald B. (National Surface Transportation Safety Center for Excellence, 2022-09-27)
    The goal of this study was to develop and demonstrate the effectiveness of a novel bicycle data acquisition system (bikeDAS) to extend the Virginia Tech Transportation Institute’s expertise in instrumentation and naturalistic data collection into the realm of bicycles and other fully or partly human-powered vehicles. The methodology incorporated the identification of a series of design considerations for effective bicycle instrumentation, including weight and balance, power, data collection capability, and mount location and design. These were addressed in a series of prototype iterations, each of which included testing in on-road situations to determine areas for improvement. The final VTTI bikeDAS is based on a weatherproofed version of the VTTI MiniDAS. The MiniDAS was developed as a low-cost, self-contained data acquisition system (DAS) for use in automobiles and motorcycles and has been adapted for use on bicycles with the addition of a rechargeable battery pack that looks and mounts to the frame like a standard water bottle. It consists of a single main unit measuring approximately 165 mm by 133 mm that contains two video cameras and numerous sensors, including GPS and a multi-axis inertial measurement unit (IMU). A mounting system has been developed to allow flexibility of placement across different types of bicycles; the typical location is attached to the head tube, which allows an unobstructed forward view, as well as views of the rider’s face and hands, and approaching vehicles, depending on bicycle geometry. This report provides detail about the needs analysis, prototyping, development, and deployment phases, and discusses areas of future development and research.
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    Evaluation of Truck Parking Needs in a Changing Regulatory Environment
    Bell, Stephen; Alden, Andrew (National Surface Transportation Safety Center for Excellence, 2024-03-15)
    Commercial driver hours-of-service rules were created to ensure that operators of heavy vehicles on US roads have opportunities to receive adequate rest during and between trips. The use of electronic logging devices to replace handwritten logs, along with the implementation of automated vehicle tracking systems, has created a potential opportunity to track the location of truck drivers with respect to their hours-of-service status. It is envisioned that this real-world driving data can inform the siting of new facilities to address a critical, national shortage of safe and convenient truck parking. This investigation sought to provide proof-of-concept for the use of electronically logged hours-of-service data to determine where additional truck parking areas are needed. A sample of this data was purchased from a commercial telematics provider, and a trusted partner was contracted to transform the acquired raw data into a format that could be used within geographic database system to identify where drivers were located as they neared the end of their allowed driving time. This database would also include the locations of existing truck parking facilities so that gaps in coverage could be identified. Unfortunately, the native format of the hours-of-service data as collected and provided was not conducive to creating a continuous record of a driver’s trips that could be synchronized in time with location data. Also, the sample set of real driving data that was provided in line with the project budget contained too few records to be of practical use. Therefore, proof-of-concept was not validated with this effort. It is likely, though, that the evolution of telematic and electronic logging systems, and the perceived value of this type of information, will result in data quality improvements that will enable the type of analysis envisioned. Examples of the problems encountered are described, and lessons learned and suggestions for future efforts have been provided.
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    Mitigating Pollution from Runoff of Roadway Deicing Salts in Virginia: A Review of Candidate Halophytes, Halophilic Microbes, and Soil Amendments for Future Remediation Efforts
    Renshaw, Andrea J. (Virginia Tech, 2021-12-20)
    Roadway deicing salt is a major pollutant of Virginia roads, damaging environmental systems, water quality, and human health. Phytoremediation of salt-affected roadside soils using salt accumulating or excreting halophytes is an inexpensive and sustainable approach to mitigating roadway pollution. An obstacle of this approach is that the highest concentrations of saline runoff occur in winter and early spring when plants are dormant. A possible solution to this challenge is adding soil amendments to increase the cation exchange capacity of soil. This would be predicted to hold Na+ and Cl– ions within the rhizosphere until spring when actively growing halophytes would absorb salt ions. Later, halophyte biomass could be harvested to effectively remove salt from a site. This review identifies candidate halophytes suitable for roadside soil desalination in Virginia. I consider potential microbial and fungal aids to support halophyte growth amidst salt stress and potentially increase salt uptake. I also review environmentally friendly soil amendments capable of binding salt for later absorption by halophytes before leached ions become pollutants.
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    Slippery Road Vehicle Early Warning System: Method Augmentation
    Druta, Cristian; Alden, Andrew (National Surface Transportation Safety Center for Excellence, 2023-03-09)
    Two prior projects conducted by the Virginia Tech Transportation Institute (VTTI) for the Federal Highway Administration (FWHA) demonstrated that small but statistically significant differences in vehicle wheel rotational rates, attributed to tire microslip, can be used to quantify the changes in tire grip that occur when pavement conditions change due to road weather. The first project established proof-of-concept by demonstrating that tire microslip increased where the pavement was covered with liquid or frozen water and confirmed that OEM wheel sensors were of sufficient resolution to determine statistically different microslip rates at the driving and free-rolling wheels. The second project introduced the concept of a traction index (TI) and explored confounding factors, such as road incline and wind. Results showed that the “noise” that resulted from apparent vehicle acceleration and wind prevented accurate measurement of TI given the constraints of sensor resolution and other factors. For the current study, researchers hypothesized that instantaneous fuel consumption rate (IFCR) and engine throttle position, available from the vehicle network, might be used to correct the calculated TI to account for the confounds. The relationship between TI and IFCR and engine throttle position was analyzed using a variety of techniques. In the end, the research team was unable to demonstrate that basic TI calculated values could be corrected using vehicle dynamic data due to factors stemming from the unsuitability of the existing road friction dataset for the application intended. Over the time spanned by these three studies, some companies have begun to use microslip and other vehicle variables as a basis for dynamic assessment of road friction. Also, vehicle data, including that which might be used to assess road weather, are now available commercially. These data sources provide opportunities for future research on the safety and environmental benefits of real-time assessment and sharing of road weather information.