Illinois State Police going ‘covert’ to catch left lane drivers. See story here. https://wgntv.com/2019/01/07/illinois-state-police-going-covert-to-catch-left-lane-drivers/
Illinois State Police officers plan to crack down on drivers who stay in the left lane on the expressways. Under the rules of the road, the left lane is only for passing or for moving over for an emergency vehicle. So in 2019, officers will use “covert vehicles” to catch violators who are staying in the left lane for longer periods of time.