LANSING (WTVB) - Michigan's blue bar and white background license plate will be phased out and replaced by a new "Pure Michigan" plate that will be standard issue from now on. That from Secretary of State Ruth Johnson, who climbed to the top of the south tower of the Mackinac Bridge this morning to unveil that new plate and a new Mackinac Bridge plate, as well. The cost for the Mighty Mac plate is an extra $5 and there is no additional cost for the Pure Michigan plate, which is being used to coordinate with the state's successful Pure Michigan tourism/advertising campaign. Now, in effect, each motorist will become a traveling mini billboard for the state. This marks the second time that the Secretary has ridden the tiny elevator inside the south tower to reach the vintage point high above the spot where Lake Michigan and Lake Huron converge just over the Straits of Mackinac