I am restoring the car and the brakes are not working yet. My driveway is on a slope. Sometimes I have to drive the car out of the garage and into the driveway. These pads give me complete confidence that my car will not crash into my house. They are strong and hold up well. You are a good weight. All I can say is that every car I've tried them on has stayed in place. These include my Jaguar XJR, GMC Denali, Mercedes GL550 and my Morris Minor project. I've tried MANY wheel chocks over the years and this is honestly the best I've found. I highly recommend them.