I'm probably stating the obvious but we'll never have anything like Waze without a lot of people consenting to share their location. The only reason Google can pull it off is because they take it from all Android phones and cars without asking. They're in a unique position to do so and this predatory approach is unlikely to be replicated in general, let alone by a FOSS project — which tends to come with certain moral values.

Keep in mind that but only do you need data, you need it to approach a certain threshold to be statistically reliable. Otherwise you get "exploits" like when those people were driving slowly up and down their street to dupe Waze into not recommending it to commuters.

And we're not even getting to the part where some people may straight out push fake locations.