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I was reviewing our standard drawings for beam guard and reading TRP-03-165-07 "Dynamic Impact Testing of w152x13.4 (W6x9) on 2:1 slopes". In that report, it is recommended that the W6x9 should be embedded 76 inches into the ground for the MGS system when the 2:1 is flush with the post.

This has generated two questions:

1. Should this embedment depth be used on non-MGS systems installed on 2:1?

2. Would this also apply to wood post installed on 2:1?

My first guess is that the embedment depth would be 76 inches for non-MGS systems, and for wood post installed on a 2:. 

For non-MGS systems (i.e., standard metric height W-beam guardrail), the center of the W6x9 steel post is to be placed at the slope break point using 7-ft long posts spaced 3-ft 1 1/2-in. on centers. The MGS design utilized 9-ft long posts at the standard post spacing. In order to make the argument for wood posts, I believe that it would be important to perform a limited number of dynamic bogie tests using 7, 8, and 9-ft wood post lengths in a sloped soil pit.