This morning I spotted @Derbyshirecc tweeting:
Be careful on the roads this morning, heavy rain means lots of standing water. Help us by reporting road flooding: http://bit.ly/2qda2d
It's a nice example that wraps up several points about councils making good use of Twitter all in one: it's got a relaxed, human tone; it provides useful information; it encourages the public to gather data to help make public services better; and by pushing the information out to people it gets it in front of their eyes in a way that passive publishing on a website doesn't.
A computer thinks the following may also be of interest:
[...] blogged this morning about a good use of Twitter by Derbyshire County Council and this afternoon I've come across a great use of Twitter in the [...]