I have an Evolve+ with ProPilot 1.5. It doesn't appear to be limited to just particular mapped roads. From some informal testing I did, it works on any road with clearly painted center and edge lines, including rural roads. It appears to work by detecting edge and center lines and will try to keep the car between them. If it loses track of the lines it makes a sound to let you know that you need to take over with steering and those green vertical(ish) lines on the display will turn off. It expects you to keep your hands on the wheel. If you take them off, after a few seconds (3? 5?), it will let you know to put them back on. Overall, it's a lot more effective and useful than I had expected.