Performance Evaluation of NDOR Mountable Curbs
Jim Holloway, Dean Sicking, Barry Rosson
Three commonly used Nebraska Department of Roads (NDOR) mountable curbs were investigated for relative safety through a combination of full-scale testing and computer simulation using the Highway-Vehicle-Object-Simulation-Model (HVOSM). The curbs that were investigated included one 4-in. and two 6-in. mountable curbs. The applicability of the model was evaluated with 23 full-scale tests, including thirteen tests on a 4-in. wedge shaped curb, two tests on a 6-in. wedge shaped curb and eight tests on a 6-in. Type I Mountable curb. The crash tests were conducted with 1800 and 4500-lb test vehicles at impact speeds of 45, 50, and 55 mph and impact angles of 5, 12.5, and 20 degrees. HVOSM was first validated against all 23 full-scale crash tests and then used to predict vehicle behaviors at alternate impact conditions. The simulation and crash test program have shown that Nebraska's mountable curbs do not have a potential for causing loss of vehicle control or vehicle destabilization when impacted in a tracking condition. Although the 6-in. mountable curbs were found to cause slightly higher vehicle motions, the differences do not appear significant enough to indicate a reduced safety performance for these curbs. Also, it was determined that the performance of W-beam guardrail can be adversely effected when used in conjunction with roadside curbs. Additionally, through a limited simulation effort of non-tracking impacts, it was determined that these curb types may be traversable over a wide range of vehicle orientations and may not be a significant cause of vehicle rollovers.
Highway Safety, Roadside Safety, Curb, Computer Simulation, Crash test, Compliance test
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