Coragyps writes:
80 mph is the posted limit on the western reaches of Interstate 10 in Texas, and there still seem to be a few folks that push 90. Though my sense is that the proportion is less than in the case of 75 with 65 being the limit.
^ anecdote, not scietifically determined ^
My rule of thumb is the top speed limit is +5 posted in Texas and +10 posted in New Mexico. As for other states generally +5 unless have other information. I also sometimes use the one hour rule - if you are passed by at least one vehicle per hour on the open freeway - they get the ticket not you.
So on I-10 this side of Kerr County, I go 85mph.
Never had a speeding ticket other than once in a school zone back in 1980.
Read not to contradict and confute, not to believe and take for granted, not to find talk and discourse, but to weigh and consider. - Francis Bacon