Rear Suspension problems of the 2005 Suzuki Aerio

After I bought my car (in late December 2004), I noticed that the rear-end twitched (very slight swings to the left & right that quickly re-grabbed the road after losing traction). This occurred every time the roads were wet or slippery, and I used it as a signal to slow down. This twitching got worse as the tires wore down, and I had replaced the rear-tires 8 months ago, and got an alignment as well. I was driving southbound on minnesota highway 77, approaching the minnesota river bridge (mile marker 7). A rainstorm had gone by earlier, so the road was wet. I had slowed down, because the car's rear-end was twitching again, and it stopped twitching, and it wasn't twitching around when I got to the bridge. As I crossed the bridge, the rear-end let go, and the car (and I) crashed into the bridges safety median, nose first. The car didn't do any twitching for the 3 minutes prior to getting onto the bridge. As a result of the rear-end letting, the car is totaled, and I was injured.