Mario Mongiardini

Experience with Cable Median Barriers in the United States: Design Standards, Policies, and Performance

A review of the experience of 23 states on the use and effectiveness of cable median barriers is presented. As of 2007, 23 states have installed more than 4,183 km (2,600 mi) of cable median barriers. Experiences of the pioneering states, such as New York, Missouri, Washington, Oregon, North Carolina and Arizona that initiated the utilization of cable median barrier in the United States are included in this paper. Results of the review show that the use of cable median barriers in depressed medians with moderate slopes had a significant effect on the reduction of cross-median crashes in many states. While these results are encouraging, occasional fatal crossover crashes penetrating the cable barrier still demand attention and improved techniques or procedures for selecting or locating cable median barrier will continue to evolve.

Acceptance criteria for validation metrics in roadside safety based on repeated full-scale crash tests

This paper proposes acceptance criteria for quantitative comparison metrics to be applied in the Verification and Validation (V&V) process of computational models used in roadside safety. Typically, the degree of verification or validation of a numerical model is assessed by qualitatively comparing the shapes of two curves, but qualitative comparisons are subjective and open to interpretation. Using quantitative comparison metrics in the V&V process allows for an objective measure of the reliability of a numerical model. Two comparison metrics were selected from a group of 16 metrics found in the literature. Acceptance criteria suitable to the typical scatter of full-scale crash tests were established by comparing ten essentially identical vehicle redirectional crash tests. Since the tests were as identical as can be achieved experimentally, the values of the quantitative metrics represented the reasonable range for the metric corresponding to matched experiments. Typical residual errors expected in full-scale tests are also discussed.

Quantitative Validation of a Finite Element Model of a Knee-Thigh-Hip Complex of a 50th Percentile Male

Traditionally the validation process of FE models is carried on by visually comparing two curves, respectively from an experimental test and the numerical simulation. A more rigorous way to quantitative compare two curves in the validation process would be provided by comparison metrics.In this work the component validation of the Finite Element model of a Knee-Thigh-Hip complex was carried on by quantitatively comparing the results from the experimental tests with the corresponding numerical curves. An LSDYNA finite element model of the lower extremities was developed and the condyle, pelvis and femur and components were carefully validated using three comparison metrics. The good match.Copyright