Yesterday something unexpected happened. I was driving on surface streets approaching a freeway on-ramp (the circular kind). Typically, as I begin my entry onto the on-ramp, I release the acc. pedal (going about 45 mph) and ride through to the bottom. This time, half-way down the ramp (with continual turning), the car starts to shake and I noticed one of the dash lights blink momentarily (the swerving looking one). I looked at the manual, and it is the "electronic stability control system" which applies the brakes "to the appropriate wheel to prevent slippage". This has not happened before, and it happened twice yesterday as I entered the freeway on 2 different occasions (2 different on-ramps). (oddly, this same light blinks when I drive over speed bumps too fast). Back wheels were just replaced (Goodyear OEM 19")..and my fronts still look good (yeah...my mistake on tire rotation. had them rotated at 6K, I think they were rotated at 12.5K during annual service, and at 18K the back wheels were pretty much gone). I would think that if any slippage occurred, it would be on the back wheels (or maybe I am not understanding the physics) Has this happened to anyone else? Is it just a problem with my tires? my driving? Or something else? or no problem at all.