> All this technology has the effect of pushing up the cost of vehicles, often for questionable minor safety improvements. DoT (and other departments) are requ

> All this technology has the effect of pushing up the cost of vehicles, often for questionable minor safety improvements. DoT (and other departments) are required to take the cost of rules into account when writing them. So for example if the cost of putting in a safety rail on a curve exceeds the cost of the lives estimated to be saved at that curve over the lifetime of the rail, it won't be installed. Different departments used to, and AFAIK still do (though I don't track this), value the price of a life differently. And it's not just the cost of the life; it's the cost of the cars damaged in a rear-end collision.