 So, for example, the high speeds of 2005 race participants led to the rules being changed for solar cars starting in the 2007 race and 2014 also.The American Solar Challenge, previously known as the 'North American Solar Challenge' and 'Sunrayce USA', features mostly collegiate teams racing in timed intervals in the United States and Canada.This race also changed rules for the most recent race due to teams reaching the regulated speed limits.