Driving during rush hour on interstate in an urban area. cars in front slowed rapidly, applied brakes to slow down, did so successfully. dynamic brake support then apparently kicked in, and forced the car to a stop, despite brake being fully released. car from behind barely able to avoid crashing into me, the driver had to swerve onto the shoulder to avoid me and ended up stopping beside my car. once car came to a stop, was able to get going again. issue has not reproduced since.