How Google Maps knows when a business is packed

David Cameron/Getty Images Add Engadget on Google: Preferred Source Google Discover Google Maps is super useful for step-by-step directions, whether you're walking, driving or taking transit to a destination. But it also offers much more than that, highlighting businesses and points of interest along the way with useful information about them. This can include star ratings, opening hours, travel distance and even suggestions about dishes or services visitors tend to love, but it can also provide real-time information as well. At a glance, it can tell you how busy a place is and how long you may be likely to wait. This information, only available if Google has sufficient data to provide it, can potentially inform your decision as to where and when to go somewhere. If you're in a rush, you don't want to stop at a very busy breakfast spot that won't get you back on the road quickly. Conversely, if you're looking for a vibe, it's best to wait until the local bar is starting to fill up. So, how does Google Maps not only know this information, but know it practically in real time? Understanding wait times and visit durations Ryan Mcvay/Getty Images When it comes to specific establishments, like restaurants, hotels, stores and coffee shops, Google uses an aggregate of anonymous data supplied by random users who have opted into the Google Maps Timeline feature. By tracking the density of devices in a certain place, Google can determine how many people are in a specific venue, and thus how busy it is, using typical traffic as a benchmark. Google works out popular times, usual wait times and how long people stay by analyzing historical data. Google Maps displays a graph that indicates times when the business may be slow and when it's likely to have queues out of the door. The average visit duration and wait time estimates are calculated using visitor patterns from the previous few weeks.  Visit duration is a great metric because it can give you an idea of how long people visit venues, like a museum, which allows you to better plan your day. Meanwhile, wait times are perfect for determining which restaurants and other service-based businesses will fit into your packed itinerary. You can even chat with Google Maps to order food, reserve hotels and more. Avoiding areas with lots of people Grant Faint/Getty Images Google also calculates how busy entire areas are, which is great for outdoor events. You can tap the "Busy area" label to see a chart for the times of day the space is usually at its busiest, along with a directory of the businesses in the vicinity. Google captures this data by combining the information it has on various locations within that locale, like stores, restaurants and even parks. It does not, however, capture data from private residences. This is calculated, once again, using anonymous data from users who have opted into Google Timeline. Google must collect enough visitor data to be able to show this information, so it might not be as readily available for less popular locales. This feature is usually limited to high-traffic zones that attract a lot of people, like a tourist town or a festival location. The data is always private, says Google, and never reveals the identity of people or the total number of people in a location. Google Maps will only tell you if a place is busy, not busy or so busy that it's probably not worth the hassle. Before opting in to Google Timeline, it's worth noting that, with this feature on, Google is essentially always tracking your activity. Bear in mind, this not only helps determine the busyness of a location, but can also prove useful in other areas. Google Maps and its sister app, Waze, use similar techniques to track traffic patterns to help you find the best driving route to your destination.  If you prefer not to be part of the process, simply turn off Google Timeline, and you won't contribute to the company's data collection.