Hi Tom,

We have 22 miles of woods roads and speeding hasn't been a big issue but it comes up.  We have signs posted for 15 MPH.  I don't think many abide by that number but signs are a first step.  Road Associations and "enforcement" of anything is problematic as I don't think the association has the power to fine, sanction, etc.  You could ask the Warden or Sheriff park and keep an eye out once in a while but there are lots of problems with that, not the least of which is really pissing of the members.  

Using a little psychology might be helpful.  Rather than actually having the Warden be there, send out a "straw poll" to everyone asking them to respond to the question "Would you recommend the Association contact law enforcement and request and officer to randomly post themselves on Association roads to enforce the speed limit?"  "Respond via email or USPS by April x,20xx.  Responses by the members and action by the Association will be kept strictly confidential."  

Doing or something like it, will probably have the desired effect.  Just thought of this....spend a couple of bucks making a turn-out on a road and have a sign made "Warden/Sheriff parking area"  That might be a bit tongue and cheek but a decent reminder to everyone that safety is important to everyone. You could even sell that to the members as a deterrent aimed at any bandits you might have in the area -- not the members.  Just some ramblings.  Good Luck