Nebraska LTAP



Ronald K. Faller

Date of this Version


Document Type



Weiland, N.A., Stolle, C.S., Reid, J.D., Faller, R.K., Bielenberg, R.W., and Lechtenberg, K.A. "MGS Dynamic Deflections and Working Widths at Lower Speeds" (2015) Nebraska Department of Roads Research Reports. Report TRP-03-314-15


The Midwest Guardrail System (MGS) has been full-scale crash tested in many configurations, including installations adjacent to slopes, with different types of wood posts, with and without blockouts, for culvert and bridge applications, and at high flare rates. Although the performance of the MGS and the dynamic deflection and working width of the barrier have been examined, little is known about the dynamic deflection and working width of the MGS when impacted at lower speeds. The MGS is a relatively low-cost barrier, and the Test Level 3 (TL-3) version could be installed for TL-2 and TL-1 applications. The barrier is expected to capture or redirect errant vehicles impacting at speeds less than or equal to those used for crash testing according to TL-3of the Manual for Assessing Safety Hardware (MASH).

Accurate dynamic deflections and working widths of the MGS when impacted at lower speeds are critical for the safe placement of guardrail to reduce the likelihood of vehicle impact with a shielded hazard in the Zone of Intrusion (ZOI) for use on level terrain and in combination with curbs. LS-DYNA computer simulation models of a 2007 Chevrolet Silverado impacting both a tangent MGS and MGS in combination with a curb at a 6-ft 3-in. (1.9-m) post spacing (i.e., standard post spacing) were calibrated against previous crash tests. Then, the model was simulated with two lower speeds and at five impact locations with a conservative soil model to determine the maximum dynamic deflection and working width of the system at TL-1 and TL-2 impact conditions of MASH.