There are parking lots in just about every community that are empty at times. These empty parking lots make for excellent Nosework practice locations.
First, you could certainly place hides on your own vehicle and have your dog search it in the empty lot. Taking your car (which your dog has already searched many times, right?) to a different location creates an new scent profile opportunity. There will be different odors from your own yard or driveway or garage and that changes just about the entire search for your dog.
Empty parking lots often have their own elements that make for great searches. Odor placed in cracks. Odor placed along curbs. Odor placed in containers which are scattered around or in patterns.
Upon inspection, the parking lot will have all sorts of imperfections and unique attributes (slopes, painted lines, garbage cans, bushes along the edges or in medians, etc.)
How else might you use an empty parking lot for search opportunities?