Yep this happened to me yesterday. In a taxi, the driver was following Google Maps, which showed a 22 min ETA, with one or two alternatives adding a minute or so. My phone was open and showed the same options. He felt certain that he knew a better route—via a highway, not a back road—and when he took that first rogue turn, Google Maps adjusted and the ETA instantly dropped to 14 min.

Google's doing it to balance traffic loads. Remember that you're the product, not the customer. Right now it's just in the testing phase, but soon the capability will be sold to municipalities and billboard owners.

I'm not really sure where I sit on this, but I have to admit it's a hell of a capability. There's some big implications of this degree of control over a population.

Is this confirmed or just your speculation? Interesting idea regardless.

are you saying it has a stake in roadway advertisements and prioritizes routes that maximize billboard views per trip? That’s pretty depressing :/ yet also capitalism I guess

I consistently will check my commute to work, as there are two roughly equal routes, either of which can be disrupted for a number of reasons. As of a few weeks ago, Google maps has stopped showing my preferred route entirely, trying to put me onto the freeway, or a toll highway 3 miles out of my way.

Once I'm about a half mile down my preferred route, Google will stop telling me to take a u-turn and actually update to the faster route, consistently saving 5-10 minutes (like 30% of the trip total).

I'm honestly baffled. My faster, preferred route takes less time, but maybe Google is prioritizing routes on freeways over arterial streets?

If Google won't show me the fastest routes I don't even feel inclined to use it. Do you have any other recommendations?

Does it to me going to JFK airport. Always tries to get me to exit at Jamaica then get back on the highway. Makes no sense

I have to double check the routes sometimes because if you drive a sufficiently long distance, it'll bring you into some creepy swamp instead of the highway.

Yup. Ended up on a gravel road in Eastern Colorado due to this feature when there was a much better route to the Highway available.