I live in Boulder and this happens all the time during ski season. When traveling towards I-70 there's a longer, more circuitous route which breaks off of Highway 6 and goes through Idaho Springs. This path is longer, but cuts off the beginning of the initial drive into the Front Range... it's also just a two lane mountain road.

Sometimes google maps will detect heavy traffic on I-70 and start re-routing drivers the other way... unfortunately this very quickly creates a bottleneck that Google Maps can't detect in time (traffic goes from 0mph to 60mph to 0mph in the mountains) so it'll continue to funnel people down that "shortcut" until the traffic essentially equalizes with the I-70 traffic.

There's an even worse side effect, as those who went through Idaho Springs eventually have to get back onto I-70 to get to the ski resorts, so now that on ramp (which is a metered on ramp) backs up, further hurting both I-70 and the "shortcut" traffic. It's a real terrible feedback loop that essentially is caused by Google Maps not being able to adequately predict how much traffic the Idaho Springs route can handle, which seems like a hard problem to solve (especially generally).

Edit: Thought about this more and realized predicting ski traffic is more or less a proxy for predicting the weather, so I highly doubt this is a fixable problem (at least in this specific case)

Would you be willing to report this to the Maps team? If not, just reply and I'll get in touch with someone about it.

Can't seem to find where to file this bug since it's not a physical mapping error. Coincidentally the Maps team is in the Boulder office, are they not? I guess I could just walk down and say hi :)

Feel free to connect me with the right people, my email is in my profile

Try this:

https://support.google.com/gmm/answer/6194894?hl=en

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Your directions were wrong

At this time, you can’t report wrong turns from your phone or tablet, but you can report them on your computer.

Open Google Maps on your computer. Click Directions directions button image. Enter the starting point and destination for the route for which your directions were wrong. In the bottom right of the map, click Report a problem.

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I'm working on getting a human contact involved.

Couldn't it take a guess based on previous actions? If it does this every weekend and keeps getting the same results, ease up a bit? If it tracks individuals, it should be able to tell when it see it diverted someone, only to have them end up in traffic.

Since in NYC taxis are a substantial portion of road traffic, I once had the idea that NYC should have a special navigation platform (maybe based on Google Maps?) that the taxis are mandated (or, more likely, highly encouraged) to follow, which would essentially load balance the traffic.

The city could include data about road closures, police & fire incidents, etc.

This might even be used to reduce traffic along bus routes, thereby increasing efficiency for them as well.

If someone works in the T&LC and wants to implement this feel free. ;)

EDIT: Note this works particularly well in Manhattan where the grid system means there are generally many routes of equal length between any two points.

> Wouldn't it mean that google maps is influencing and even creating the traffic patterns ?

I'm pretty sure I've observed this in the wild. Occasionally there's a major accident on a freeway in Denver that totally stops traffic. People that know the area well enough hop off the first exit they can and find the most straightforward way over to a major arterial road running in the same direction. Maps sometimes comes up with the theoretically-fastest route that requires lots of turns through neighborhoods, so you'll see a whole conga line of cars piling through suburban streets and congesting the whole area.

It'll be interesting to see if Google starts to proactively load balance these sorts of situations - send people on several different routes at once to keep traffic flowing.

This problem is an active area of academic research in the transport operations/planning field. It's generally known as "concentration and overreaction".

A classic example would be if a road is severely congested, and satnavs started advising drivers to take an alternative, smaller road, if too many people get the same advice that road will then end up even more congested and delay the people who followed the advice to change routes even more.

http://www.jstor.org/stable/42747332?seq=1#page_scan_tab_con... is a good starting point if you are interested in reading more about this area.

It's similar to the 'flip-flopping' problem (I'm sure there's a technical term for it) - actions based on feedback from a sensor changing the sensor reading, triggering a different reaction.

A common example I've seen used is: Automatic headlights on a car turning on in the dark. When the headlights turn on when you're in a garage or tunnel, they can create enough ambient light to trick the sensor into thinking it's light, and turning the headlights off. The solution here is to add a delay into the reaction.

I'm wondering what a solution is to a problem with mapping - is it add a delay to re-routing traffic? Or rerouting traffic randomly? Or spread traffic out over a number of routes? It's made harder by the fact that Google in this case won't be routing all traffic - just a subset.

Waze does this, and Google owns Waze.

There is a policy on the backend of google maps to diversify the best routes they suggest to users. It's like A/B testing where they show different responses to users who make the same requests

This article is about Waze, but I can remember reading the same thing about google maps:

http://www.latimes.com/local/california/la-me-california-com... (Ctrl-f "variety")

I totally had that same thought when using google maps to navigate LA.

I wondered what happens when you enter some sort of harmonic oscillation of people trying to evade traffic with alternate routes matching the delay of Google re-routing them.

The easy fix would i guess be doing a round-robin of alternate routes..

Yeah it seems like at some point you'll end up in a traffic "bubble" where you don't actually get the "fastest" route but the one that thinks will make the roads fastest for everyone.

Yeah... we're secretly hoping for some version of https://en.wikipedia.org/wiki/Schrödinger's_cat

I thought Google Maps used the Android phone location to know the busy road?

And anyone actively using maps.