Driving on public roads PSA:

[milktree]

Turn signals: The purpose of a turn signal is to indicate that you're about to do something weird, not to explain why you just did something weird. In other words, use them *before*, not during, and certainly not after, you change lanes or turn onto a side street or driveway.

Or, said in a way that even your most daft Boston driver can understand:

If you want to change lanes, or turn in/out of a side street/driveway, use your turn signals long enough in advance that everyone else on the road can know what you're going to do *before* you start to slow down or pull out into traffic or whatever change in your driving you're about to do.