Ask HN: Anyone heard of an 'open-source' or 'grassroots' infrastructure project?

Open-source projects are obviously a big topic in the programming world, with some major contributions coming through such projects. I was wondering if anyone has ever heard of similar projects for public infrastructure whereby a project is established for some aim and experts from different disciplines chip in to create a comprehensive plan as a sort of community driven non-commercial project.

To give some context, I live in Sydney, a city I believe needs some serious public transport infrastructure built to better serve its ever growing population. Unfortunately, it seems that the expected costs and short political focus of our politicians pretty much means there is little in the way of a comprehensive plan for the city's public transport infrastructure.

Rather than the usual complaining with fellow Sydneysiders over chardonnays while waiting for some prophet of public transport to appear in the political space I thought it would be an interesting idea for a group to form around building such a comprehensive plan from a grassroots level. The assumption been that as/if the project matured it would gain buy-in from the populace and political clout from the ruling class.

So to reiterate my question, has anyone heard of any such projects coming out of other cities? If so, what was their story? Did they succeed?