Usually, roads can be used to circulate vehicles or for pedestrians and parks can be used to keep vehicles without any art decoration. This is the concept of ordinary people towards those public places. 

To most artists, those places can be exploited as subjects to prove their gifted abilities either from innate or through study. 

With very similar objective, artist Peter Gibson, known as Roadsworth, had transformed streets and parks in Montreal into beautiful view with decoration of amazing artistic shapes. 

You can see more on roadsworth