When did the speed limit on the 710 get lowered to 55 mph?

[Occidental Tourist]

I noticed recently that the entire 710 freeway is now signed for 55 mph, down from 65.  This is AFTER they finished installing all of the new safety improvements and interchanges.  Given how fast traffic goes on that freeway, I can't imagine there's a traffic engineering study to support such a low speed limit.

Does anyone have any information on why this change was implemented?

[jfs1988]

Well, it does have a lot of truck traffic because of the ports & the industrial cities.