15mph might be slow to a racer or hobbyist who does regular long distance riding, but it's about typical for commuters and the very casual end of hobbyists. Maybe it's slow downhill. It's definitely not slow to pedestrians: a collision with a cyclist going 15 mph can be quite injurious.

This doesn't have anything to do with commuters, it's hikers vs mountain bikers in a recreational area.

I wonder if enforcement tends to be more strict when a hiker happens to be present.

In previous reports I've seen, they generally speed gun at a blind downhill corner. It's a good choice: the biker is speeding in a location which might have a hiker, so the guys getting the tickets are in fact the ones endangering others.

A collision between a cyclist and a tree at 15 mph can be injurious. Cyclists try to miss obstacles, pedestrians included, for their own safety.

So do most auto drivers. It is a fact that lower speeds correlate to fewer accidents and accidents with generally less bad outcomes, though.

There's got to be a floor somewhere. Do you think 5 mph is safer than 6? What about 1 mph?

Life is injurious, stay home if you don't like it.

Why not: life has laws, stay home if you don't like them.

Mandatory foam suits for all then? How long until "mountain bikes" are required to have black boxes? 2024 CA: where you need a "bike license".

It's too bad the mountain bike hall of fame did not stay in Crested Butte rather than move to the overcommercialized aspect offered by Marin county.

What's overcommercialized about it? It looks downright mom and pop to me. (Full disclosure: I live in Fairfax and donated to its opening.)

There's not much in this town that looks overcommercialized, to be honest. It's a pretty laid-back town.

On a shared walk/bike trail? Sounds not that slow.

That's actually the crux of the problem: there are no dedicated mountain bike trails on public land in Marin. So people who want to mountain bike use the fire roads, and often skip over to the 'single track' where bikes are disallowed. (For the record, I've personally never done this... but I'm also not a 'real' mountain biker.)

And of course, there are irresponsible mountain bikers out there who take risks, scare hikers, and deserve tickets. And those few bad actors lead to rules like this one... I think.

Really depends on the trail.