These spy shots were taken in Independence, Colorado, a few weeks ago by eagle-eyed Autoweek reader Dick K. It looks to be the next Ford Explorer, judging by the shape, size and grille. However, the shooter talked to one of the drivers who said it was a diesel, which is very intriguing (assuming the driver wasn't lying). Could Ford be prepping a crossover that takes advantage of the F-150's new 3.0-liter diesel engine?
Ford's popular three-row Explorer has been on its current platform since 2012, so it's plausible a complete redesign would be in the testing phases right now. These shots look more like a facelift, but keep in mind prototypes would use existing stock parts for testing — that honeycomb grille, which looks plucked from the police-version Explorer, for example, and the rims, which looks to be a set of stock rollers made for test vehicles. There is a chance it's a new Lincoln three-row vehicle too, considering the current Flex-based MKT should have been put out to pasture years ago.
Take your best guess in the comments.