The Bend in the road at Bonneville salt flats.

I double checked where we stayed by using Google Maps. It's the Leppy Pass Road Exit. Google Map it by plugging in Bonneville Salt Flats then zoom in and notice that across from the Salt Flats Café is a large dirt lot. That's where we stayed. It looks like it may be Exit 4. Leppy Pass Road turns into Bonneville Speedway Road.