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56 CHAPTER 6 CRASH TESTING AND FURTHER EVALUATION OF PRELIMINARY AESTHETIC DESIGN GUIDELINES Once the preliminary guidelines were developed using the ort 350, "Safety performance of a highway appurtenance finite element simulations, a full-scale crash-testing phase was cannot be measured directly but can be judged on the basis conducted. The results of these crash tests were used to for- of three factors: structural adequacy, occupant risk, and vehi- mulate the final design guidelines by assisting with refinement cle trajectory after collision." Accordingly, the following of the internal energy thresholds used to establish acceptable safety evaluation criteria from Table 5.1 of NCHRP Report and unacceptable impact performance. A summary of details 350 were used to evaluate the crash tests reported herein: of the crash-testing phase are presented in this chapter. Structural Adequacy A. Test article should contain and redirect the vehicle; CRASH TEST CONDITIONS AND the vehicle should not penetrate, underride, or over- EVALUATION CRITERIA ride the installation, although controlled lateral de- A brief description of NCHRP Report 350 test conditions flection of the test article is acceptable. and evaluation criteria is provided in the following sections. Occupant Risk D. Detached elements, fragments, or other debris from the test article should not penetrate or show potential NCHRP Report 350 Test Designations for penetrating the occupant compartment or present an undue hazard to other traffic, pedestrians, or per- According to NCHRP Report 350, two crash tests are sonnel in a work zone. Deformation of, or intrusions required for Test Level 3 (TL-3) evaluation of length-of-need into, the occupant compartment that could cause seri- longitudinal barriers: ous injuries should not be permitted. F. The vehicle should remain upright during and after NCHRP Report 350 Test Designation 3-10: 820C collision, although moderate roll, pitching, and yaw- vehicle impacting the length-of-need section at a speed ing are acceptable. of 100 km/h with the vehicle bumper at an impact angle H. Occupant impact velocities should satisfy the fol- of 20 degrees. lowing: NCHRP Report 350 Test Designation 3-11: 2000P Longitudinal and Lateral Occupant Impact vehicle impacting the length-of-need section at a speed Velocity--m/s of 100 km/h with the vehicle bumper at an impact angle of 25 degrees. Preferred Maximum 9 12 The small-car test is conducted for evaluating the overall I. Occupant ridedown accelerations should satisfy the performance characteristics of the length-of-need section of following: a longitudinal barrier in general and occupant risks in partic- Longitudinal and Lateral Occupant Ridedown ular. The pickup truck test is performed for the purpose of Accelerations--g evaluating the strength of the section in containing and re- Preferred Maximum directing the larger and heavier vehicle. Occupant risks are 15 20 of foremost concern in the evaluation of both tests. Vehicle Trajectory K. After collision, it is preferable that the vehicle's tra- NCHRP Report 350 and Other Evaluation Criteria jectory not intrude into adjacent traffic lanes. M. The exit angle from the test article preferably should Crash tests were evaluated in accordance with the criteria be less than 60% of the test impact angle, measured presented in NCHRP Report 350. As stated in NCHRP Rep- at time of vehicle loss of contact with the test device.