I usually go the speed limit because I'm a boring driver but if someone in front of me is going slower than the speed limit I'll speed up to get around them as fast as I can but then I'll slow back down to the speed limit when I'm far enough in front of them.
I live a long way from a city so I can get away with going the speed limit but if I'm driving in a city then I'll keep up with traffic if it's going faster.
At my age?? You've got to be kidding! When I was younger I was able to keep up with the commute traffic during rush hour, but I sure can't run that fast anymore.