What's this about over 30 being scary? Bikes get more stable with speed, you only fall over when you go too SLOW. I was topping out in the upper 30's in middle school on a Schwinn Traveler (with aero bars). That was on a nice downhill in my parents neighborhood in suburban Northern Va. I would make several runs down that road each bike ride!
Later in life, moved west and hit 47 or so on the same bike in Northern Id where they have real hills.
Now in Mi (what's a hill?) and getting back in shape so mid 30's is about typical top speed on the parts of road that have an incline in the downward direction. Working to improve that, but don't see 40's coming without more gravational assistance.