Here is a picture showing the mess that the motorists left on the Walnut Creek Trail greenway that I reported yesterday. As you can see, this covers the entire width of the trail, and is a safety hazard for cyclists. A simple solution to prevent this would be to place two fences parallel to each other but nearly perpendicular to the greenway and separated from each other by 6 feet or so. One fence would span the length from the trail to the woods, the other from the woods almost to the trail. This would allow maintenance vehicles to pass, but would prevent illegal motorists from hitting the gravel section at full speed, thereby preventing them from spraying gravel.