During my commute today, I tried to imagine how a car driving 10-20 mph faster than mine could come up behind me without my noticing.
According to the account, the Smart driver was going about 65. She said that the impaired driver hit her at about 75 mph. Assuming the range to be closer to 15 mph, I figured out that it's probably a good habit, as a defensive driver, to look in the rearview mirror periodically. Because I drive so slowly (avg 55 when the traffic is thin), I constantly look behind me to see if I need to adjust my driving style (mainly by speeding up temporarily if there is a truck gaining on me, tho there are other reasons I'd make adjustments).
I calculated that the Smart driver in the scenario above had about 10-15 seconds, max, to react. Still, that lower limit is quite enough to make a careful adjustment, like switching lanes if possible, slowing down (which would increase the likelihood of an impact but would also minimize the result), or even honking (as odd as it might seem, you sometimes have to honk at a driver behind you). Best option of all, however, would have been to speed up a bit while waiting for the other driver to notice her and get out of her lane.
When not about to change lanes, I'm sure many people forget to look in the rearview mirror. Under normal circ's, it's still a good idea to do so.
I'm glad she's ok -- remarkable story! -- and wanted to post this as a suggestion that might help other drivers.