Were your brake lights on when you lost the Volvo? Maybe it's not that helpful when stopped... (Heck, people rear-end FIRE TRUCKS with the whole array of lights going. It seems like this is a hole with no bottom...)
Gen II Volts not only pay attention to the pedal but also the slowing rate, and turn on the brake lights when the rules call for it. I can't remember what it is in meters per sec^2, but it works out to about 0.1g. https://www.youtube.com/watch?v=_F4iyghT-qA