One mechanical way to reduce risk of personal injury in single and twin reciprocating engine powered craft, which are the majority of GA flown for pleasure and some business, is the whole airframe ballistic parachute and individual occupant airbag. The former, if used when needed typically prevents death, the latter automatically prevents head and torso injury from frontal impact…moreso than four and five point shoulder harnesses. And, as Paul as mentioned, the use of a helmet also will reduce injury. Personally, I’d go with the ballistic chute and airbag, setting personal minimums and sticking with them, and realizing that if I absolutely must be “there” on a schedule, to either drive or fly commercially. Small price to pay for preventing life long injury and/or death.