There have been some concerns raised regarding the construction of wide (15 - 18 feet) median shoulders in conjunction with concrete median barrier. The concern is that shoulders this wide will increase the likelihood of a head on collision with the barrier. I’m familiar with the studies that established barrier offset relative to potential to override/underrun a barrier. Is there research that addresses risk of high impact angle relative to distance from the barrier?
Previous research in NCHRP 17-22 looked at this issue. Dr. Cody Stolle from our staff worked on that effort.
I spoke with him regarding this issue. He had a couple of insights.
As such, it would seem rational to presume that the performance of most barriers will not change drastically due to an increase in the shoulder width. Some studies have shown that larger offsets, like cable median barriers in the center of a wide median, do tend to see higher impact angles. However, your case does not seem to be that severe.
Let me know if that answers your question or if you need further information.