Nebraska LTAP


Date of this Version


Document Type



Meyer, D.T., Reid, J.D., Lechtenberg, K.A., Bielenberg, R.W., and Faller, R.K.. (2017). "Increased Span Length for the MGS Long-Span Guardrail System Part II: Full-Scale Crash Testing" NDOT Research Report TRP-03-339-17.


The objective of this research study was to design and evaluate the MGS long-span design for use with unsupported spans greater than 25 ft (7.6 m). Two full-scale crash tests were conducted to evaluate the MGS long-span system with increased span lengths and the use of UBSP posts adjacent to the long span. Both tests were conducted according to the TL- 3 criteria outlined in MASH. Both test nos. MGSLS-1 and MGSLS-2 were conducted with the 2270P vehicle impacting their respective critical impact points at a speed of 62 mph (100 km/h) and an angle of 25 degrees. Test no. MGSLS-1 was conducted to evaluate the potential for vehicle instability by selecting a critical impact point that maximized the interaction of the front wheel of the pickup truck with the wing wall of the culvert. Test no. MGSLS-2 was designed to evaluate the structural capacity of the system by selecting a critical impact point that maximized the potential for pocketing, wheel snag, and rail rupture.

Test no. MGSLS-1 resulted in the vehicle being captured and redirected smoothly by the barrier system with all vehicle decelerations being within the recommended occupant risk limits. Therefore, test no. MGSLS-1 was deemed successful according to the TL-3 safety performance criteria found in MASH. Test no. MGSLS-2 resulted in the vehicle penetrating the barrier and creating multiple detached fragments that could present a safety hazard to oncoming traffic or the occupants of the vehicle. Therefore, test no. MGSLS-2 was deemed unsuccessful according to the TL-3 safety performance criteria.