I drive my Model S, delivered July 2016, on some two lane roads here in Northeast MA. Those roads include US Highway 1 and bunches of others. Since I started using it on those roads, the speed at which autosteer may be engaged has been limited to the posted speed limit plus 5MPH. But recently, without a software update, that limitation has been removed on US 1. It now uses the same rules as on freeways. The limitation is still in place on other two lane roads. What's going on? Is Tesla sending the cars some kind of road-configuration data? They must be. One strange thing about it. US 1 around here is gnarlier than many other two lane roads. The shoulder width varies more than some other roads. The pavement is dirtier and streakier, which can baffle the lane-holding features. And, in places US 1 has more tight curves and strange intersections, due to the fact that it's been around for three centuries or so.