Why do you consider crime rates of more serious crimes, yet instead of counting the number of road speed law violators, you count only the number of citations for speeding? Like drug possession laws, road speed law enforcement is highly selective. You can't get a picture of overall criminality by measuring arrest and citation rates.
How fast would speed limits change if automated detection led to automatic fines for any speeding? We're already close; the only reason it hasn't been implemented is that everyone knows it would upend traffic speed laws through public outrage. (I realize there's the theoretical legal problem of identifying the driver, but that hasn't stopped many locales from using red light and speeding cameras and holding the registered owner responsible for fines.)