While moving across the states, I was towing our 2004 Prius on a flat bed and we were rear ended by a lifted pick up causing some damage to the rear left side. It seemed to be only body damage. However, after taking it off the trailer and driving it around to see if it was drivable, it drove extremely sluggish as if the brakes were being applied but the power train was acting normally. For example, when at a complete stop on a flat surface, when releasing my foot off the brake, the car barely moved. These lights showed up on the dash in the picture provided. I decided to look underneath the Prius to inspect if there was any further damage. I noticed this one little gray arm that was snapped in half that was connected to what seems to be a sensor and cannot figure out what it could be. I also discovered that after lifting the rear wheels off the floor, the right rear wheel would not spin freely. I attached some pictures of the snapped piece and am hoping someone can help me figure out what it is and if there is anything else I should check for given the explanation.