On the freeway, probably not much over 75-80. No reason to go faster than that.
Some facts the average person doesn't comprehend...
An average commute to work is about 15 miles.
Freeway speed limits are normally around 65mph.
If you could drive 65 the entire way to work, it would take you just under 14 minutes
If you decide to speed and drive 80, it still takes you 11.25 minutes
I don't get why people feel the need to speed so much just to save 2.5 minutes on their way to work or wherever they are going other than the adrenaline rush they maybe feel by thinkign they are so cool for driving fast....
Even if you are on a 100 mile trip, you still only save 10-15 minutes if you drive that fast the entire way, which is normally not possible.