This has been an ongoing gripe of mine for this and my previous 2 S's. This is the only car I have ever owned that you cannot resume the speed you were going prior to touching the brake (or in the case of the Tesla by moving the cruise stalk away from you to disengage cruise.) The cruise control is tied in with the setting on the Speed Assist page, however there is noting on that page that would indicate the connection. It is always a guess as to what speed the car will accelerate after disengaging the cruise and then reengaging by momentarily pulling the cruise stalk towards you. For example: the Speed Assist is set for +12 (relative) and I am cruising at 40 in a 35mph zone (with sign). I either touch the brake or push the stalk away from me but when I reengage the cruise control by pulling the stalk towards me the car will accelerate to 47 mph (35 + 12).