When I'm running on cruise control, at say 70, and I come up behind a car moving slower, as the Prime engages the brakes, do my brake lights come on? In other words, does the guy behind me know I'm slowing down?
Yes, but it takes more braking that you might think for the brake lights to activate. It will go all the way to about "B-mode" level of braking before the brake lights come on. In my opinion that might confuse following drivers. It could be dangerous because it gives them slightly less reaction time compared to using the brake pedal, where the lights come on at the lightest press of the pedal. So most of the time if the car ahead is just a little slower or if there's enough following distance, the brake lights won't come on. If the car ahead of you is going much slower or coming to a stop the brake lights will come on. I tested it by driving with my bike on the bike rack on the back, so I could see the lights shining on the bike in the rearview mirror.
It shouldn't be any more of an issue than when the car ahead is coasting in gear, or even has downshifted a gear. The person behind you doesn't know if you are using dynamic cruise control or not, and should be paying attention to you and the distance between.
Thanks for the info, particularly the idea that, although the lights do come on, the system isn't as sensitive as it would be under manual control. And I agree Xray22, I could have looked for this in the manual. But I much prefer hearing from people who may know the answer and be able to add some insight. And that's exactly what II got in this case.
