Well I think that if Shan Alexandra wants to reduce speed on the ridge, then I am all for it. And I don't mind if they put Humps on the road either. Street lighting would of course be desirable. However good sense should prevail. I picked up the following comment on Yahoo Answers, I don't know the Author, but it seems clear to me
"
It all depends on the presence or not of street lighting.
A 30mph speed limit is in place if there are street lights. For the speed limit to be higher there would need to be repeater signs about every 200 metres.
If there are no street lights and no signs then the national speed limit applies which is 60mph on a single carriageway, a lower speed limit has to have repeater signs when there are no street lights"
Source unknown
Hope that makes sense