[Lintner5]

By my records, the states adopting provisions to allow black pants include:
Colorado
Connecticut
Illinois
Iowa
Kentucky
Maine
Michigan
Minnesota
Missouri
Montana
New Jersey
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Dakota
Tennessee
Vermont
Virginia
Washington
Wisconsin

Based on my cartography skills, I'd say most states not lying south of Missouri have adopted the black pants while southern states have been more resistant with noted exceptions of Oklahoma, Tennessee, and North Carolina). Also, I'm uncertain of the black pants status in many states. I know Georgia and Kansas have considered the idea and denied black pants in 2010.