A word of warning to Magic Valley motorists…. slow down and curb aggressive driving habits.  Idaho State Police officers have just begun an education enforcement campaign that targets both speeders and aggressive drivers on all Idaho roads. Officers say they'll be stepping up speed patrols until the end of April.  ISP and the Idaho Transportation Department say speed is the number one contributing factor in deadly and serious injury crashes in the State. The agency also says in 2010, aggressive driving contributed to 52 percent of all crashes in Idaho, and crashes involving speed also cost over a billion dollars.