Cigroller has summed up exactly what I was thinking and exactly what I do.
While it is never possible to totally eliminate being rear-ended by distracted drivers and tailgaters, what Cigroller posted is your best defense.
Does it work? Well, I have only been rear-ended once–circa 1978–and that was a low-speed incident that caused no damage to my Volvo, despite significant damage to the front of the Buick that hit me at about 10 mph.
If you do everything that Cigroller has suggested, you will limit the chance of a repeat incident.