Possibly millions of drivers have seen a large juniper decorated for Christmas on the Interstate 17 median in southern Yavapai County. But few people know who offers this simple holiday gesture to brighten the day for interstate travelers. The tree has been adorned with plentiful, imaginative decorations between Thanksgiving and Christmas every year for at least two decades. It is located on the I-17 median less than a mile south of the Badger Springs exit #256, the last exit north of Sunset Point Rest Area. The Daily Courier found one of the few people who know more about the mysterious tree trimmers, but he's not talking. "I know who started it, but I'm not going to go into that," said Tom Foster, who worked for the Arizona Department of Transportation in this region from 1966 to 2005, the last seven years as district engineer. Foster is quick to point out that neither ADOT nor the Arizona Department of Public Safety condones the annual decorating feat, because it is quite dangerous for anyone to pull a vehicle over in that vicinity or walk across I-17. But he won't budge about the name(s) of the decorators, saying they choose to be anonymous. "I heard there's some elves that got to looking at how bleak we were ... and people weren't celebrating Christmas very well," Foster said. "They thought (the decorations) are a good way to brighten the drive between here and Phoenix." He estimated the "elves" have been decorating the tree for 20 or 30 years. "But don't stop on the road," Foster warned potential photographers or gawkers. "That's not what Santa wants."