Litigation was pursued by the Sierra Club in 1998-1999, on grounds of environmental damage from the gravel portion of the road. The environmental damage was caused primarily by the of gravel that washed away annually, the same amount that needed to be hauled up the mountain each year in order to maintain the road surface. Environmental damage included alpine ponds and wetlands becoming filled with gravel, and layers of gravel averaging deep covering the forest floor below. Pursuant to the settlement agreed by the Sierra Club and the City of Colorado Springs, the unpaved portion of the Pikes Peak Highway became a hard-surface road, despite concerns that such a project would radically change the nature of the annual automobile and motorcycle race. The paving project was completed on October 1, 2011.