[wongarsu]

"Alternate routes" are still normal roads people travel on. Since the travel time of a path is just the sum of the travel time of all path segments you only need people traveling every road to estimate the total time of any path. Path finding is well understood with many algorithmic solutions, so there is no reason to use machine learning.

Google's implementation is impressive, but I see no reason why it would benefit from people traveling suboptimal paths.

[taneq]

It doesn't have to be doing gradient descent on a neural network to be machine learning. You could easily generate small perturbations to generated routes if they didn't add much time and took the driver down an under-monitored road.

[majormajor]

Some path times are destination-dependent in ways Google doesn't seem to handle well, like certain turns or freeway onramps vs the regular lanes next to them. You would need people "testing" those parts, not just the regular path parts.

[krallja]

Google Maps is not just path finding; it also takes real-time traffic info into account.

[wongarsu]

Which is still just path finding: estimate travel time for each segment, use travel time instead of distance as edge cost.

Don't take that as a dismissal of Google maps: it's the most impressive path finder I know, working with high performance over long distances, taking into account real time information, and calculating meaningful alternative routes to choose from. It's an impressive piece of technology that actually makes the world a better place by saving humanity a lot of travel time that can now be spent on better activities.

Google Maps would certainly be high on my list of best inventions of the last few decades. At the same time the routing is just a good path finder with a good travel time estimator informed by real time data.

[mannykannot]

Compared to distance, travel time is a more complex and nuanced variable. There are more things that a route planner could do, and I suspect that Google maps (and others) are doing some of them. They include taking into account the variance in the time to transit each route segment (which might be, for example, weather-dependent), preferring simpler routes (including taking account of statistics on missed turns), and taking into account the effect of its -- and others' -- recommendations on the flow of traffic (or even on public safety.)

[Retric]

Gathering data is required to do travel estimates. If Google was using handset data to update congestion information, it would want to send a percentage of users down sub optimal routes to verify they are sub optimal.

[tripzilch]

I would be very upset if they did this, though. I'm not Google's test subject and it would be pretty f%$#@! dehumanizing if they treated me that way.

I'm not a bloody ant or part of their hyper-organism.