Glass covered berms

On Tuesday 6/10/2008 the ride was great until... Our average speed was 13.6 mph and the distance ended up right at 18 miles. We commented on how much broken glass was on the berm of the roadway, when we were about half way through the ride. One of our riders flatted and found the cause was a piece of glass that worked its way through the tire. Flats are frustrating, but the day was bright and the company good. We've had enough flats this year. I've often wished that people didn't throw glass out of their cars. It is yet another difficulty of shareing the road with automobiles.