Doing single car runs for qualifying with a field of 8 or so cars is pretty lengthy. At Daytona you are talking 16-18 minutes depending on how fluid the field is at getting the next driver out on the track. Personally at the speedways, I don't see a benefit to qualifying at all (with the exception of a point or what not for being on the pole). There is so much passing on the speedways that starting position just isn't important.