While traveling in Ireland, I was introduced to a new word: eejit. At first I thought that this was simply the Irish pronunciation of "idiot," but I was astonished to see it spelled the way it is in the prominent Irish Times newspaper. After hearing it repeatedly, I started to get the sense that it was exactly what I'd been looking for: a term that pretty much sums up what makes a bad driver so bad.
'It takes all kinds.' That's what my mother used to say with a shrug every time she encountered someone who behaved in a way she found offensive. I'm a bit less tolerant than Mom was. For the occasions when forgiveness eludes me, I have created a few new Circles of Hell that Dante may have missed. Please add your own contributions in the comments below; here's my list.