Seatbelts Make Drivers Less Cautious

I believe in the statement "seatbelts make drivers less cautious" because they provide a false sense of security. When the economist Steven Landsberg suggests we should all drive around with a spear pointing straight into our chest, he is making the point that if we are scared enough, we will take extreme measures to save our lives. Yes, it would be frustrating and less productive to have to drive around at 5 miles per hour everywhere we go, however, how many lives would this save in the long run? Seatbelts are a good form of saving lives, but should we be more worried about saving lives or preventing crashes?