I drove from Sydney to the other side of Newcastle last week and used cruise control on the M1. From what I have read cruise control doesn't work on very low speeds. From my experience I found that you have to get used to the distance set between the you and the car or truck in front because in the case of trucks particularly you could end up at a much lower speed on a rise. If you need to overtake you either have to accelerate to close the gap before overtaking or move straight into the next lane but make sure you have the room with cars in that lane to cover the exta distance. My preference would be after doing it a few times is to accelerate to close the gap and then overtake. I always bring the car to the speed I want with the accelerator and then set cruise control. I hope this is helpful.h