The customers are there, but the supply of used cars is not. Inventory levels have been dropping since early summer. New car dealers are not seeing trade-ins as new car sales continue to be depressed. Cash for Clunkers may have crushed 700,000 used vehicles. The result will be lower sales volume in September. New car dealers are already bracing for lower new cars sales as a result of the success of Cash for Clunkers. This could be a tragic double hit to some dealers already on shaky financial ground.