A drive-in restaurant is one where a customer can drive in with an automobile for service. For example, customers park their vehicles and are usually served by staff who walk out to take orders and return with food, encouraging diners to remain parked while they eat. Often, the restaurant staff attach a serving tray to a window of the vehicle. It is usually distinguished from a drive-through. At a drive-through restaurant, conversely, customers wait in a line and pass by one or more windows to order, pay, and receive their food.