When leaving work on 1/6/22, I didn't let my car warm up for more than 1 minute because I was in a hurry to get home. It was very cold - I think -10 if I remember right - and I had just passed through an intersection about 2 blocks from work where road construction closed the road to one lane. The car in front of me stopped because someone in front of him was turning. I had plenty of time to stop & hit my brakes but had no response, much like not having power brakes, but the pedal felt very firm. As cold as it was, there was no ice or snow & the road was dry. I had no traction control or ABS lights come on & ended up rear-ending the car in front of me. The police came & made a report & I came home & checked KIA forums to see if this had ever happened to anyone else but didn't find anything. I explained it to my KIA service advisor but they found nothing wrong & had no explanation. I thought I had maybe imagined it until it happened again, also on a very cold morning, about 2 weeks later in my own driveway. Just no response of the brakes. I couldn't push the pedal hard enough to stop the car. I also mentioned it to my insurance adjuster who just said to let them know if I found out anything further, which I didn't. I never thought to report it here until my husband had an issue with his car recently & was advised to do so. Even extreme cold should not affect a system as important as the brakes on a car & I believe this is a major safety concern. My accident was minor because