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124 APPENDIX B Research Need Statement for Expanding and Enhancing the Research Products
125 RESEARCH NEED STATEMENT FOR EXPANDING AND ENHANCING THE RESEARCH PRODUCTS Background NCHRP Project 15-55: Guidance to Predict and Mitigate Dynamic Hydroplaning on Roadways has produced a novel, transformational approach to estimate hydroplaning potential based on the physics behind hydroplaning. Using advanced fluid dynamic, tire, and vehicle response models, the project has developed a new way to assess the safety risks associated with vehicle hydroplaning. This novel approach represents a quantum leap with respect to traditional approaches that were based on a handful of experimental studies (e.g., PAVDRN). NCHRP Project 15-55 has produced an advanced Integrated Hydroplaning Model, which can be used to simulate and study various types of road, environment, and vehicle combinations, and a Hydroplaning Risk Assessment Tool to provide highway engineers with practical and simple means for assessing the impact of roadway features and other factors on hydroplaning potential. The model and tool were validated using available, yet limited, data sets, and used to develop a Guide for Assessing and Mitigating Hydroplaning Potential. During the second panel meeting, the project panel recognized the benefits of the new approach and recommended that the project team prepare a proposal for additional work to further validate and improve the models and enhance the practicality of tools to facilitate their implementation and adoption. The work proposed in this research need statement is aimed at achieving an even more accurate and practical tool to support agency efforts for assessing and mitigating hydroplaning. The goal of the prepared research need statement is to refine the models developed under NCHRP 15-55 (water accumulation, vehicle, tire, and tire-water-pavement interaction), verify the hydroplaning risk assessment process with new experimental results, and produce a more practical tool to facilitate the implementation of the outcomes of the project. Existing guidelines for pavement design are based on a limited number of experimental studies and a definition of hydroplaning that emphasizes a single hydroplaning speed without a fundamental understanding of the mechanisms by which hydroplaning develops. Understanding the fundamentals of hydroplaning allows interpretation of hydroplaning potential and risk without resorting to a single go/no-go speed. There is a spectrum of conditions in which hydroplaning can occur, and experimental verification of these mechanisms will allow a wide range of safety concerns to be addressed in a rigorous manner. The ultimate products of these efforts would be an enhanced tool for assessing hydroplaning potential and risk. The proposed enhancements include three possible research efforts: 1. Improve the water accumulation model; 2. Refine the models to predict hydroplaning potential for Light Vehicles ; and 3. Develop an enhanced Hydroplaning Risk Assessment Tool. B.1. Improve the Water Accumulation Model Objectives: ï¼ Obtain new experimental data using a vehicle with a non-contact device for measuring water thickness.
126 ï¼ Verify and refine the developed accumulation model by conducting additional computer simulations under a wider range of conditions. ï¼ Refine and enhance the water accumulation model using the new experimental and computer-generated data. Tasks: 1. Acquire a mobile device for measuring water thickness (e.g., Lufft MARWIS-UMB - Mobile Advanced Road Weather Information Sensor) and install it in a vehicle. 2. Conduct initial verification/calibration testing under controlled conditions at the Virginia Smart Roads (including its surface street and rural road extensions). 3. Obtain new experimental data using the instrumented vehicle on road sections with known geometry close to weather stations to collect validation data. 4. Conduct additional computer simulation to verify and refine the developed water accumulation model under a wider range of conditions. 5. Refine the existing water accumulation model using the experimental data. Funding: $250,000 Research Period: 18 months B.2. Refine the Models to Predict Hydroplaning Potential for Light Vehicles Objectives: ï¼ Obtain experimental results using an instrumented vehicle on a test track to perform standard vehicle dynamics maneuvers. ï¼ Refine existing models and adjust the developed standards for hydroplaning potential and risk as needed. Tasks: 1. Perform a set of vehicle tests on test surfaces with varying water film thicknesses and tire tread depths under a set of standard cornering and braking maneuvers (e.g., constant radius test, J-hook). 2. Refine and validate the fluid-solid interaction model for wet pavement interactions with the tire using the experimental results. 3. Refine and validate vehicle and hydroplaning potential and risk models using the experimental results from vehicle testing. 4. Enhance the simple graphical user interface and code to estimate hydroplaning potential and risk based on the design guidelines and the enhanced models. Funding: $300,000 Research Period: 18 months
127 B.3. Develop an Enhanced Hydroplaning Risk Assessment Tool Objectives: ï¼ Enhance the Integrated Hydroplaning Model. ï¼ Produce an updated, more practical version of the Hydroplaning Risk Assessment Tool. Tasks: 1. Enhance the Integrated Hydroplaning Model using the updated water accumulation and hydroplaning potential prediction models. 2. Implement the hydroplaning risk assessment approach proposed in section 3.6 of the NCHRP 15-55 Final Report. 3. Produce an updated and more practical version of the simple Hydroplaning Risk Assessment Tool using additional simulations produced with the enhanced Integrated Hydroplaning Model and the experimental data collected. 4. Verify the impact of the water film thickness on wet accident rates using information collected in Virginia and other states if available. Funding: $250,000 Research Period: 12 months
