Bang for the buck is seriously in question here. Lets say there are 12M new cars sold each year (some estimates are higher) and go with the cost estimate from the article of $400/vehicle average. By this calculation, cost would be nearly $5B. That's MORE THAN $10M per life saved AND $100,000 per injury avoided.

($10M*292 + $100,000*18,000 = $4.72B vice $4.8B cost).

Wow! An NPRM has to pass a number of thresholds for cost-effectiveness, alternatives, etc to make it into law. These numbers seem WAY too high to pass muster. What are the relative costs would be for back-up sensors (vice cameras)? The relative safety beneifts? Honestly, this smells like poorly done homework.

Another benefit is the update rate of ADS-B. The sweep for en route radar is 11s. So the closure rate for two aircraft heading in opposite directions could be as much as 20 miles per sweep. In contrast, ADS-B could provide position updates to the controller every second. In the terminal area, the sweep rate is ~5 seconds, and aircraft are of course going more slowly. Still, there are potentially significant benefits for the final approach, especially for parallel runways where a big potential concern is aircraft blundering off of their approach and into an aircraft on the parallel approach.