Google and Apple Maps rival explains why their ETA estimates are always off

Ever wonder why your estimated time of arrival (ETA) at a destination that you used Google Maps or Apple Maps to navigate to never matches up with the initial ETA estimate? For example, let's say that you are traveling from Ludlow, Vermont to Moreau, New York. After tapping the destination into Google Maps, it shows that the drive will take 1 hour and 40 minutes allowing you to get to your destination by 2:45 pm.

But by the time your journey ends, it is 2:55 pm and you're ten minutes late. What happened? Google Maps and Apple Maps rival TomTom recently said in a blog post that "We rely on estimated times of arrival (ETAs) now more than ever. Whether we’re waiting on a package, food delivery or taxi ride, an accurate ETA is essential. The problem with ETAs is that they are hard to calculate accurately – and this can lead to both dissatisfied customers and disgruntled drivers."

First, why should it matter if your ETA is off by a few minutes? TomTom points out that deliveries could arrive too early or too late which frustrates consumers. A package that arrives too early when no one is home to receive it has a bulls-eye on it that says "steal me." And a late food delivery could result in food being too cold by the time it gets to your house. And a ride share that arrives at the airport late might force you to run through the airport as O.J. Simpson used to in television commercials for Hertz back in the day.

Drivers trying to pick up minutes on their ETA tend to drive faster with no regard to the usual rules of the road. In 2019 Tom Tom spoke with ride-hailing companies (such as Lyft and Uber) and food delivery companies and was told that having an accurate ETA was one of the biggest problems they face in their businesses. That's because there are so many unpredictable variables that go into figuring out when you will arrive at point "B" after leaving from point "A."

Such variables include the weather, driver behavior, and traffic. Part of the problem is that each company has a different reason to provide an accurate ETA. Delivery firms need reliable ETAs while ride-hailing and other firms dealing with commuters want to get their customers from one place to another as fast as possible.

Inaccurate ETAs can occur because some drivers are aggressive and will speed through yellow lights, drive well above the speed limit, and take other chances. Some drivers are conservative and will stop at a yellow light and drive well below the speed limit. Some companies use algorithms to match deliveries with certain drivers. TomTom says that "These algorithms are the 'secret sauce' behind route and ETA planning and perform extremely complex calculations that companies own and may vary from business to business."

To improve ETA accuracy TomTom suggests the use of historical data that show how fast traffic flows through certain roads at specific times of the day. Mix that with Real-Time traffic (TomTom has a system that updates real-time traffic every 30 seconds). It is also important to figure information about the road into ETA calculations. The mapping firm points out that "The more accurate the maps, the better for drivers and customers. Road details like curvature, gradient, speed limits, traffic lights, specific traffic rules and lane information are all important to consider."

It might sound surprising, but TomTom says that the best route might be one that is longer but is more likely to deliver a more accurate ETA than another route with more traffic lights or accidents. TomTom adds that obtaining an accurate ETA is "both an art and a science."