The justification for a traffic stop that led to a drunken driving charge against Amy Lynn Mueller was a deputy sheriff’s belief that Mueller violated the statute on improper lane usage, called ILU, when the driver’s side tires of her Jeep touched — but didn’t cross — the yellow center line on Illinois Route 31 in McHenry County and her passenger side tires twice touched — but didn’t cross — the white fog line.Section 11-709(a) of the Illinois Vehicle Code says: “A …