Yesterday in the HOV at 75+ mph a truck lost a roll of carpet padding just in front of the car ahead of me. He swerved, and suddenly, the roll was coming at me diagonally. It was over 12" in diameter and about 8 feet long. My view was blocked by the car in front until he swerved. There was nobody right next to me so I swerved to the right (no time to brake). Long story short: the Prius handled perfectly, no sway, or slide, and it tracked perfectly the whole time. I just had time to touch the brakes, and steer 1/2 a lane to the right. I was pleasantly surprised! I autocross my Subaru, and never thought the Prius would handle an unexpected "slalom" move so well. I have lots more confidence now about its handling. BTW: stock tires 35,000 mile, 1/2 worn Goodyears, 42/40 psi and a BT brace. Bring on the freeway furniture, me and the Pri are ready for it! B)
It probably didn't hurt that you have VSC. I just read recently that stability control will be mandatory on all cars starting in 2012. Finally!!!