Thesis (Ph. D.)--Worcester Polytechnic Institute. / Keywords: design guidelines; NCHRP Report 350; finite element analysis; impact; curbs; guardrail; curb and barrier combinations. Includes bibliographical references (p. 310-316).

Indiana University-Purdue University Indianapolis (IUPUI) / Over the years, car driving experience has evolved drastically. Many new and useful technologies have emerged, which have enhanced safety and reliability measures. The Automotive world is now trying to build capabilities for driverless or vehicle assisted driving. Building capabilities for driverless cars practically means first developing training methods, then training the machine, evaluating the test results, and then based on testing results; develop a confidence interval for trusting the machine. One of the critical models is the model adopting the Road Departure Assisting Techniques (RDAT). These techniques are primarily the standards for alleviating the risk of roadside fatalities. The different models developed or proposed for RDAT falls under “The Road Departure Mitigation System” (RDMS). But, almost every RDMS to date has over-reliance on the presence and the quality of the lane markings. In the absence of lane markings or of proper lane markings, these RDMS are unreliable. Therefore, RDMS requires new references such as roadside objects and road edges for detecting road departures. This new system should propose and establish a standard for RDMS testing with roadside objects. As the foremost task, this new system requires the creation of a testing environment consisting of soft, robust, and reusable surrogates. Critically, these surrogates must have comparable sensors characteristics to those of real roadside objects from various commonly used object detection sensors on the vehicles such as camera, radar, and LIDAR. One of such everyday roadside objects is the curbs. For developing a surrogate for the curb, the first step is to recognize what the roadside objects should look like concerning different sensors, and the next step is to design and develop a surrogate curb that successfully follows the properties of the real roadside objects. This thesis first demonstrates and proposes the methods for extracting the color, Radar reflectivity, and the LiDAR reflectance properties of real roadside curbs. That is, the study deals with what all color combinations and patterns represent the US roadside curbs, what should be the range of Radar reflectivity values, and LiDAR reflectance bounds that a surrogate curb should satisfy. The later part of the thesis illustrates methods and steps on how to mimic the extracted properties, design a surrogate curb as per federal standards, and then develop a surrogate curb. Finally, the surrogate curbs were subjected to crash tests for testing their robustness.

"The potential hazard of using curbs on high-speed roadways has been a concern for highway designers for almost half a century. Curbs extend 75-200 mm above the road surface for appreciable distances and are located very near the edge of the traveled way, thus, they constitute a continuous hazard for motorist. Curbs are sometimes used in combination with guardrails or other roadside safety barriers. Full-scale crash testing has demonstrated that inadequate design and placement of these systems can result in vehicles vaulting, underriding or rupturing a strong-post guardrail system though the mechanisms for these failures are not well understood. For these reasons, the use of curbs has generally been discouraged on high-speed roadways. Curbs are often essential, however, because of restricted right-of-way, drainage considerations, access control, delineation and other curb functions. Thus, there is a need for nationally recognized guidelines for the design and use of curbs. The primary purpose of this study was to develop design guidelines for the use of curbs and curb-barrier combinations on roadways with operating speeds greater than 60 km/hr. The research presented herein identifies common types of curbs that can be used safely and effectively on high-speed roadways and also identifies the proper combination and placement of curbs and barriers that will allow the traffic barriers to safely contain and redirect an impacting vehicle. Finite element models of curbs and curb-guardrail systems were developed, and the finite element program, LS-DYNA, was used to investigate the event of a vehicle traversing several curb types. Finite element analysis was also used in the analysis of a vehicle impacting a number of curb-guardrail combinations. The results obtained from these analyses were synthesized with the results of previous studies, which involved full-scale crash testing, computer simulation, and other methods. The combined information was then used to develop a set of guidelines for using curbs and curb-barrier combinations on high-speed roadways."

<p></p><p>The study deals with one of the critical aspects of the Road Departure Mitigation System. The first part of the study finds out what all color combinations and patterns represent the US roadside curbs, what should be the range of Radar Reflectivity values, and LiDAR Reflectance bounds that a surrogate curb should satisfy. The later part of the thesis illustrates methods and steps on how to mimic the extracted properties, design a surrogate curb as per federal standards, and then develop a surrogate curb.</p><br><p></p>