The major automakers reported a big boost in sales for August. It was the first monthly gain in total new vehicle sales in almost two years, and the reason for it turns out to be clear: it came directly after the federal “Cash for Clunkers” program spurred 700,000 people to upgrade their gas guzzling clunkers in exchange for $3 billion in cash. We take a look at what the new numbers say about the industry for the longer-term with New York Times auto reporter, Nick Bunkley.