I assume they would need to accept whatever rides come their way under such a scheme, as otherwise they could just idle and collect money

Edit: From the proposal: "drivers would earn a minimum of approximately $21 per hour while on a trip, including the costs of their average expenses"

So yeah, it looks like it would only apply to time spent on a drive. I hope it at least includes the time it takes to get to a customer as well. I had an interesting conversation with a Lyft driver a while back who explained that if you're mainly moving people short distances in the suburbs, you're hardly breaking even. It would be neat if a pay structure could incentivise being available in lower-demand areas but I guess we're not there yet