2. Seatbelts are not as useful as they could be
3. Seatbelts are not useful
4. Seatbelts need to be improved
5. Seatbelts need to be outlawed
6. Getting rid of all seatbelts will cause people to drive more slowly and more carefully and will also make car crashes easier to escape.
I love the counterintuitive nature of the Hypothesis, Giants, and I’ll be very happy to help you search for academic sources. Of course, there’s no way you’ll be able to conduct NEW research into eliminating seat belts (and, by the way, airbags, too). But perhaps looking BACKWARDS you can find a way to measure whether drivers have become more reckless SINCE the introduction of what are now standard safety features.
Is that what you’re looking for?