. >> any woman that gets in a is hooked or -- >> meet kim potocki, mother to two girls, part-time little league coach. >> are you practicing? >> yes. >> reporter: who, when she's not carpooling the kids, can crash them up with the best of them. >> it's an adrenaline. it's something different. you don't normally get to go hit people. >> reporter: she's prepping for her biggest competition so far. where she'll be squaring off against 300 top derby drivers, including her husband, chris. >> not the first time that's happened. >> reporter: building the cars from scratch is a family affair. the kids pitching in. >> the cars are engineered to do one thing on the road and we're doing something different with them to do what you need it to do, to last, that's part of the fun of it. >> that will get me to the floor. >> reporter: they strip out anything that can break or burn. >> he's cutting the old motor welded on the frame. >> reporter: mom's car has to survive crashing into this. that's vicki schutte. >> in 15 years, i've won three features. >> reporter: a welder by day, a useful trade in this