There are almost zero details in the original story on Contact Music, but a story like this doesn't really need details. The key point, Julia Roberts uses biodiesel is all the detail you need. We're not going to be making biodiesel with her, and we won't be going for a ride in the car (Mercedes? New? Used? Who knows), so what's to know? We don't even know where she'll fill up – or what blend she'll use.
Apparently her husband, Dannny Moder, bought her the new car because she said a.) she wants a car that "smells like French fries" and b.) she wanted something bigger than a Prius for when her kids grow up. Nothing like instant gratification.
[Source: Contact Music via Ecorazzi]