[aerohead]

I did a post on aft-bodies and spoilers.Vans and wagons(SUVs) don't produce lift and are not proper candidates for "spoilers".Since they do have enormous wakes,they are candidates for boat-tailing.The CRV does have some plan tapering to it's body,so it enjoys a little pressure recovery before the flow breaks away at the rear.The rub is that SUVs,vans,and wagons, are the worst candidates for streamlining.If you've read my installment on rooflines you'll see why.Any significant drag reduction would only come from a tail of significant length.Again,you can read about it.Some of the devices you see on backs of these types of vehicles is to direct a downwash of air from the roof,to blow stuff away from the rear windscreen,to help keep the glass clean.While air IS directed into the wake(which you might think reduces the wake drag) the device itself has its own drag,which in poorly-conceived designs add to overall drag.Body contour-following additions,as Darin has done on the MetroMPG Swift are a form of the Kamm truncated roof and are one of the "sure-bets" for drag reduction on these body styles.