I do go "too fast" on the Greenway, but only about 12-15 when I approach anyone on foot, or slower bikers, and even walking speed as I wait patiently for a clear path around them. I don't pass on the corners, ever, and I know where to be cautious even when it looks clear. 18mph in the stretches between them isn't speeding.

Anyone following me for even half a mile should have gotten the picture from the frequent slow/surge if nothing else. We're going slowly around other people, and giving them 3 or 4 feet, and we're going to slow into choke points even if, following me, you can't see them yet. After thousands of commutes over that path, I just react to them ahead of time.

added: you've pointed out the main reason I don't have an e-bike. For my particular commute and distance, a Georgia street-legal e-bike would be no faster and likely slower than my road bike commutes. I might like one for other reasons, but the large majority of my miles lately are commutes.