John F is right, The main concern is in the farm yard, not the long straight downhill section. If you are actually doing 5 mph, the dust really isn't kicked up. Also while dust is one of the concerns, there are other reasons for the speed limit. Vehicles driving too fast near the barn can scare the horses. Also there are dogs and kids around the house and barn who may not be looking for cars. And if you somehow missed it, there are also many large trucks, bucket loaders, and other equipment that have large blind spots when operating.

The slower speed limit addresses all of these issues. While the issue of loud music has never been mentioned by the farm I also make sure it is a reasonable volume when pulling into the farm  again to make sure not to scare the horses, be able to hear kids, dogs, equipment, and it is courteous to john-paul

As far as visitors to the club, there are 5 mph signs both as you enter off the main road, and as you approach the barn from the field side. Also on all of the pages that give directions to the field, it clearly states "Speed Limit through the farm yard is 5 MPH for all GMRC members and guests (NO EXCEPTIONS)!" With exception of people that just drive by and see us flying, I would guess most if not all of the people get directions from our website, or one of our members. Which when I give directions I make sure to mention the 5 mph rule, as all of our members should be doing.