2023 Chevy bolt has a hand 'regenerative brake'. I was using it while driving in traffic. My speed was around 40 mph when the car in front of me abruptly stopped. The distance between us was approximately 30 ft. I immediately switched from hand brake to foot brake and the pedal felt soft and there was a delay in response to foot brake. I rear ended the vehicle in front of me causing damages to both vehicles. This had happened in August 2023. I called the manufacture to let them know what happened and they told that they will pass the information. I made a call to them in December of 2023. My vehicle was not inspected for this issue as I am not sure who can help me with this problem. There were no warning lights before the accident. Ever since the accident I have tested switching from 'hand brake' to foot brake and always feel a softer pedal and a slight delay in response. I believe this issue was a main factor for the accident as in my over 10 years of driving experience I have never had an accident before. I believe that the 'hand brake' is using electric motor while foot brake uses regular hydraulic system and they are not adjusted properly when are switched in between.