South Lake Shore Drive starting or ending at Interstate 55 and starting or ending at 47th street depending on you direction of travel. Speed limited is posted at 45 on what is basically a highway. Radar fitted Chicago cops sit in turn arounds or on entrance ramps at 31st or Oakwood. While I’ve never been pulled over doing 50-55, traffic is still moving quick and you can get caught up by following someone doing 60 without thinking twice about it since the road is so open.