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I was looking at the deflection values in Table 5.4 of the RDG (page 5-25).  I'm confused where these deflection values are measured from.  Are they deflection values or working width (e.g. barrier width plus deflection).  If they are just deflection do I just and the width of the system to get working width?

The values in the table come from several sources. To the best of my knowledge, the simulations were performed by Kitty Hancock using the NARD code. At the time of this analysis, our industry was not yet using the working width terminology. As such, I believe that the simulation results just depict dynamic deflections. Some crash test results are also referenced in the table. These MwRSF tests were also very dated. As such, dynamic deflections were likely used as well.

A Pooled Fund study published in 2015 investigated the MGS impacted with and without curbs to MASH TL-1, TL-2, and TL-3 impact conditions. The working widths identified in that study were:

No curb: TL-1 = 37.6"

TL-2 = 49.3"

TL-3 = 60.3"

6" behind AASHTO Type B Curb:

TL-1 = 30.5"

TL-2 = 40.9"

TL-3 = 49.6"

https://mwrsf.unl.edu/reportResult.php?reportId=307

The Texas A&M Transportation Institute performed a study of the dynamic deflections and working widths of 31-in. tall, nested W-beam guardrail systems at full, half, and quarter post spacings according to MASH Tl-3 impact conditions. The results were documented here: https://www.roadsidepooledfund.org/wp-content/uploads/2014/11/TRNo-603481-Final.pdf/

Full post spacing: 46"

Half-post spacing: 26" 

Quarter-post spacing: 17"

In the first study, the guardrail deflections were calibrated based on full-scale crash testing and simulations were performed at 1/4-post spacing using LS-DYNA. In the TTI study, the simulations were performed using Barrier VII and nested guardrail conditions, only at MASH TL-3 impact conditions.