Urban Farming

[Capt_Bowman]

A well laid road is several feet thick of tarmac (base coat, wear coat) and levels of coarse and fine stone. You might also then have fuel / oil contamination of the underlying soil if the road is old and has been in use for years... that is assuming the bulk of the topsoil was not removed as part of the construction process.

I suspect you'd reclaim parks, gardens, median strips and the like before you started breaking up roads.

But that is just my view and based on UK roads.