This statement is not quite correct. The setting indicates the speed, as an absolute offset of the currently detected speed limit, at which the car will emit au

This statement is not quite correct. The setting indicates the speed, as an absolute offset of the currently detected speed limit, at which the car will emit audible or visual warnings that the driver has set the cruise-control speed too fast. That setting is also the speed for a specific gesture that sets the cruise control to the maximum speed for the circumstances. E.g., if the posted speed limit is 45 and the setting is 5, then the gesture sets cruise control to 50 mph. The car never adjusts the cruise-control set speed by itself, with one exception: if the current road has no center divider, then it clamps the current speed to no more than the posted speed limit + 5 mph. The term "clamps" is in the programming sense: if cruise-control is already set below that speed, nothing changes. The car never increases the cruise-control set speed. Only the driver can do that. In other words, the driver had already set the cruise control to 75 mph and likely had the setting at speed limit + 10, which is aggressive. The reason the car accelerated is because it determined there were no cars ahead of it traveling at a speed lower than the set speed. Unfortunately, that conclusion was absolutely correct.