That's heartbreaking. 20 mph on a mixed-use trail is dangerously reckless, unless you get a long empty stretch out in the countryside. There are always groups

That's heartbreaking. 20 mph on a mixed-use trail is dangerously reckless, unless you get a long empty stretch out in the countryside. There are always groups of 4+ pedestrians who will suddenly spread out and block both lanes completely, with almost zero warning. If you can't react to that without an accident, you're going way too fast. It would be nice if pedestrians would stay in the correct lane, but it's never going to happen. Even if you're only going 5 mph, you've rung a loud bell, and you've clearly said, "Passing on your left" (if that's the local trail's convention), then half the group will immediately spread into the left lane. And the other half will block the right. This is the most basic fact of mixed-use trail safety.