Lots of speed limits are arbitrary. I think speeding is fine as long as you're respecting road conditions, like you seem to do. Your gf needs to know that politicians are not civil engineers.

What bothers me is how little experience and actual ability Americans can have to be given the full legal right to operate a 2,500lb weapon. How is texting while driving not banned yet? My gf got her license at age 18 with approx. 45 mins of driving experience, lifetime. The state of TX then said "YOU ARE LEGALLY PROFICIENT ENOUGH TO DRIVE ON THE HIGHWAY DESPITE NOT HAVING SEEN YOU DO SO"