Delano is one of those small, Central Valley cities that is typical of California. Delano is an agricultural center, located in one of the most fertile areas of the world (while people outside of California tend to think of the state as being one big beach, the majority of it is actually excellent agricultural land), it is home to numerous farms, related businesses, a politically and socially conservative population (something else common in California, despite the stereotype), and, apparently, a butt-load of ghosts. One of these ghosts is a phantom hitchhiker that haunts Browning Road in southern Delano.
There is no consensus on the origin of the ghost, though the most common story seems to be that she was a young woman who was crossing the street early one morning when she was struck by a speeding vehicle. Regardless, she is said to appear on the side of the road, sometimes looking as if she's about to cross, other times looking as if she's trying to flag a ride. Some stories tell that she actually appears in the backseat of cars driving down Browning Road (shades of Highway 152?), while others hold that the ghost has moved into the path of oncoming traffic only to vanish as the cars swerve to avoid her.
People posting to internet forums* report that, in addition to trying to cross the street, dodge traffic, and catch a ride, the young woman also will run after cars driving on Browning Road, and has been heard latching on to the car's undercarriage and messing about with the machinery. Two posters report making an effort to attract the ghost's attention - one reports that he and his passenger saw the ghost appear next to the car, and they quickly high-tailed it out of there; the other reports that they drove up and down the road looking for the ghost, and finally stopped and exited the car, mocking it. Upon returning to their vehicle, they saw the spirit in the back seat, though it promptly vanished, leaving a cold spot in the back of the car.
There is at least one variation on the story that holds that the ghost is not a phantom hitchhiker, but rather the spirits of two men who appear as shaodws and leap at cars. And one variation on the "ghost appears in the backseat" element says that the ghost is not seen in the backseat, but can be felt nudging the driver from the back seat.
*Ahhh, publication on the Illustrious Internet! Well-vetted and accurate. You can believe everything that you read there, especially if it's posted by someone with the monniker of Sluggo!
Commentary: I have complained before about how the ease of copying and pasting on the internet can lead to folklore stagnating. In this case, though, the use of the internet appears to have led to the stories flourishing and mutating in interesting ways. While most of the posts on the internet message board threads about this story bare all of the marks of being someone wanting to tell tall tales, they are, nonetheless, great variations on, and continuations of, the original story. When one searches, there is, of course, a fair amount of cutting-and-pasting between different sites. But there is also a good deal of originality, and that's part of what makes ghost stories so wonderful.
One thing that this story brings to mind, at least for me, is that the generall classification of a ghost story often doesn't quite describe it. This one is often described as a vanishing hitchhiker, and there are elements of that tale here, but the ghost just as often simply appears near the car, chases the car, or appears within the car, all without anyone trying to give her a ride. This is, in some ways, similar to Ressurection Mary, where the ghost does sometimes go for a ride, but just as often is said to do something else altogether.
I also like the variation that describes her latching on to the underside of a car and mucking about with it, making her similar to a gremlin. I wonder if this is an example of two stories coming together, or of one story simply gaining attributes similar to another, but independently.
Sources: Weird Fresno, Strange USA Forums, Unsolvedmsyeries.com (AKA, the web page that time forgot), Oddly, a Facebook page, Shadowlands.net