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Why Google Told Drivers to Drive a Longer Way On Purpose (sfgate.com)

(Tuesday September 08, 2026 @04:34AM (EditorDavid) from the my-Waze-or-the-highways dept.)


"A team at Google's research arm used Google Maps to reroute a small portion of drivers in 10 U.S. cities," [1]reports SFGate — including San Francisco and Los Angeles.

"Through their experiment, which was published [2]in the journal Nature Cities in June, the researchers sought to evenly spread traffic down more corridors as the drivers head to similar destinations, in the hopes of reducing congestion."

> The experiments nudged up vehicle speeds by 2% on average on the congested roads, and shortened travel times by a modest 0.7%. Scientists have long thought that traffic could be eased this way, and this now demonstrates how it could actually work in the real world.

>

> The researchers collected data on weekdays in the 10 cities, which included Seattle, Salt Lake City, Chicago and Atlanta. While they studied a variety of types of roads, from city streets to highways, they found that in cities such as Los Angeles where they targeted highways, their diversions had the biggest effect, with driving speeds in those areas increasing by about 4.6%. Most cities, though, saw a smaller improvement with speeds across them increasing by just 0.5% during peak times. The Google study's findings confirm what other researchers have long suspected, said Michael Manville, a professor of urban planning at UCLA who was not involved in the study. "This is a pretty nice empirical illustration of a longstanding idea," he said. If a clogged traffic artery is on the verge of a long delay, he said, rerouting a small number of vehicles away from the bottleneck produces a "not gigantic but noticeable result...."

>

> As with other traffic interventions, there's a risk that Google's approach to spreading traffic could backfire. This concept, known as "induced demand," also applies to efforts like adding a lane to a critical highway, which temporarily relieves congestion, until traffic rises again. "You can do this, but you cannot be too successful, because if you are too successful, then more people will start driving, and essentially you'll be back to ground zero," [said Alexandre Bayen, a co-author of the study and director of UC Berkeley's Center for Information Technology Research in the Interest of Society]. "That's why when we did the study, we only operated at the margin." The idea is to make minor improvements, enough to matter in the aggregate but not so significant that people notice and start driving more, canceling those improvements...

>

> The Google Research study also considered the potential environmental benefits of its traffic improvements. The paper highlights the carbon dioxide emission reductions resulting from the slightly smoother traffic flow and shortened travel times, which add up to a savings of about 1,000 metric tons annually. That's equivalent to the emissions of about 200 vehicles, a drop in the bucket for cities with millions of cars, the majority of which are still gas guzzlers, even in San Francisco and LA. Bayen acknowledges that while emphasizing the cumulative benefit if such efforts were sustained for a longer time. For Manville, the study is a useful proof of concept. "It is a demonstration that if we managed roads better, air would probably be cleaner," he said.

According to the article, "Google's study might not just be a one-off, and city officials could decide to make use of the Google research findings, Bayen said, such as by trying to improve traffic congestion on a larger scale..."

"Google declined SFGATE's requests for comment on whether the company informed city authorities or rerouted drivers about the study," the article points out.



[1] https://www.sfgate.com/tech/article/google-traffic-wrong-way-22416144.php

[2] https://www.nature.com/articles/s44284-026-00443-x



Experiencing this firsthand (Score:3, Informative)

by fjo3 ( 1399739 )

Had this happen three times in the last month or two in Northern California. As long as I follow the new route strictly, I usually get there at about the same time I would have otherwise, but with a brand new view of the cityscape / rural landscape. Went for a nice river drive last week, 10/10 so far.

Re: (Score:2)

by geekmux ( 1040042 )

> Had this happen three times in the last month or two in Northern California. As long as I follow the new route strictly, I usually get there at about the same time I would have otherwise, but with a brand new view of the cityscape / rural landscape. Went for a nice river drive last week, 10/10 so far.

(Me) ”I’m just curious; what time did Google suggest you leave for your trip?”

(You) ”Well..OK..Yeah, technically it was three AM.”

(Me) ”Mmhmm. Just wanted to confirm the ‘best’ time to survive California travel and enjoy a cityscape or two.”

Induced demand is BS (Score:2)

by TheMiddleRoad ( 1153113 )

When the road widens, it meets a need, which means more people consume it. When they make the road too expensive to consume, people consume it less. We should have double-decker freeways and people zipping along from wherever they want to be. If you want to deal with sprawl, then plan sensibly. Do not use the roads as a misery choke point. Traffic engineers are fucking assholes, every last one of them.

Re: (Score:3)

by serviscope_minor ( 664417 )

Induced demand is BS [...]Traffic engineers are fucking assholes, every last one of them.

You can't wish away reality jut because you don't like it.

We should have double-decker freeways and people zipping along from wherever they want to be.

How much more tax are you prepared to pay to support that?

Re: (Score:3)

by 0123456 ( 636235 )

> You can't wish away reality jut because you don't like it.

Yet he's absolutely correct. There's a demand for more travel, which governments refuse to fill. When new roads are finally built which meet those demands, the communists shriek "LOOK! THE NEW ROADS ARE ALREADY CONGESTED! WE MUST STOP BUILDING ROADS!" and midwits nod sagely because The Expert Is Always Right.

> How much more tax are you prepared to pay to support that?

It's weird how we used to be able to build these things when society was muc

Re: (Score:2)

by r1348 ( 2567295 )

> It's weird how we used to be able to build these things when society was much poorer.

You mean when there were far fewer cars around, and they were much smaller? Yeah, I wonder too.

Re: (Score:2)

by serviscope_minor ( 664417 )

When new roads are finally built which meet those demands, the communists shriek "LOOK! THE NEW ROADS ARE ALREADY CONGESTED!

Are you denying that the "communists", i.e. people with basic powers of observation are correct about the level of congestion?

It sounds to me that as a dyed in the wool right winger, you dislike the rational conclusion of the observation of reality therefore you believe that reality must be wrong.

It's weird how we used to be able to build these things when society was much poorer.

Ah r

Re: Induced demand is BS (Score:2)

by blue trane ( 110704 )

"How much more tax are you willing to pay to support that?"

How much more tax do I currently pay for mass transit I never use? $500 car tabs, anyone?

Gemini:

"The Regional Transit Authority (RTA) tax rate on car tabs for residents living within the Sound Transit boundaries in King County is 1.1%. This translates to $110 per year for every $10,000 of your vehicle's calculated value. [...] The Regional Transit Authority (RTA) tax is strictly used to fund the construction, expansion, and daily operations of the S

Re: (Score:1)

by Anonymous Coward

> "How much more tax are you willing to pay to support that?"

> How much more tax do I currently pay for mass transit I never use? $500 car tabs, anyone?

If you're driving, every person riding mass transit means less traffic for you. Seems like a benefit.

Re: (Score:2)

by Sique ( 173459 )

This is not exactly true. Demand for traffic is not static and just sitting there, waiting to be fulfilled. Demand indeed can be induced by an offering. If you know that from point A to point B, commute times will be X, you think twice about moving to point A if you work at point B, or taking up a job at point B, if you are already living at point A. But if due to road construction and adding a new lane, traffic times will lower to X-t, suddenly living at A and working at B will become viable, people living

Induced Demand is full of holes, change my mind (Score:2)

by GameboyRMH ( 1153867 )

Induced demand is plainly a theory with lots of holes. It sees no utility in moving any greater number of people the same distance in the same amount of time, according to induced demand theory that's a complete waste. If induced demand were true, Japan's Wangan should be clogged with traffic instead of empty enough for ultra-high-speed street racing, and China's highways to newly-built empty towns should probably be full of traffic for some reason too.

The best debunking of the idea I've run across comes fr

Re: (Score:2)

by serviscope_minor ( 664417 )

Induced demand is plainly a theory with lots of holes.

It is not.

. It sees no utility

Ah yes, they theory doesn't address your feeling therefore it's bad! Induced demand is about traffic numbers. Utility of those numbers irrelevant to the numbers.

according to induced demand theory that's a complete waste.

I love how when people hate the results of a theory they just make shit up about the theory and attack that. Induced demand has NOTHING TO SAY about the value of the demand.

If induced demand were true[...]

Th

Induced demand (Score:3, Insightful)

by Sneftel ( 15416 )

> As with other traffic interventions, there's a risk that Google's approach to spreading traffic could backfire. This concept, known as "induced demand," also applies to efforts like adding a lane to a critical highway, which temporarily relieves congestion, until traffic rises again. "You can do this, but you cannot be too successful, because if you are too successful, then more people will start driving, and essentially you'll be back to ground zeroâ¦"

Oh fuck all the way off.

This idea of "induced demand" always comes up in the context of traffic improvements, as though the goal of traffic design is to keep people from driving. (We had a sale on apples, and everyone bought our apples! Damn this counterintuitive induced demand!) Add a bypass and now it's full of cars? Good! That was the whole point: to help people live where they want to live and get to where they want to get to. Every car making up that new traffic jam is being driven by someone who is, on balance, willing to sit through it because of the positive effects it's had on them.

You can point to pollution and carbon emissions and freeways splitting communities, of course. There are plenty of reasons not to want more roads, and plenty of reasons to want to force people to adopt different living habits than they want to. But if that's your aim, at least be honest about it.

Re: (Score:2)

by thegarbz ( 1787294 )

I think you fundamentally misunderstand the point. The point of induced demand is that it can't solve traffic congestion, it can only further intrench car dependency. It's counter-intuitive to its own goal, as you said the point is to get people where they want to get to, and the best way of doing that is to provide them with a method of doing so that doesn't waste their lives.

Induced demand is a concept unique to overcrowded individual mobility sources, specifically driving. On the flip side you can do som

Re: Induced demand (Score:2)

by Sneftel ( 15416 )

> the best way of doing that is to provide them with a method of doing so that doesn't waste their lives

Thanks for your concern. Please refer to my fuck off from above. You donâ(TM)t get to decide what I want.

> You don't drive because you want to drive. You drive because planners and designers have ultimately created an environment which made it either the best or maybe the only option for you.

You're wrong on both accounts as well as wrong fundamentally. I personally donâ(TM)t want to drive. I quite dislike driving. I prefer a short walking commute, and when that's not practical I prefer mass transit. But for many people, driving is the only practical way to simultaneously accomplish several aspects of the life they want to live, including being housed in a very low-density area, wor

Re: (Score:2)

by serviscope_minor ( 664417 )

Thanks for your concern. Please refer to my fuck off from above. You donÃ(TM)t get to decide what I want.

So you're saying you do want a method that wastes your life? Because that's the alternative to a method which doesn't.

hose desires are not a matter of planning.

They absolutely are. Do you have some sort of theory where American are fundamentally lazier on a genetic than other people? If not, then the desire to not walk must come from somewhere else.

Don't go so far the rabbit hole of social engineeri

Re: (Score:2)

by bsolar ( 1176767 )

> I personally donâ(TM)t want to drive. I quite dislike driving. I prefer a short walking commute, and when that's not practical I prefer mass transit. But for many people, driving is the only practical way to simultaneously accomplish several aspects of the life they want to live, including being housed in a very low-density area, working in a high density area, commuting without significant walking sections, etc. Those desires are not a matter of planning.

IMHO they actually are. As example, the typical American residential low-density suburb is the result of significant planning and the way it's structured is a fundamental reason for car reliance. Other countries have made different planning decisions and that leads to less reliance on cars.

I currently don't need a car: I can do everything I need with either mass transit or a bicycle, but if I were transplanted in a typical American suburb I will almost guaranteed switch to a car. People will do what is a co

Re: (Score:3)

by 2TecTom ( 311314 )

car dependency is baked into large tract single use developments, fix the corrupt development process and then maybe you can reduse the need for travel in the first place

people don't just decide to drive around for little reason

Re: (Score:2)

by serviscope_minor ( 664417 )

people don't just decide to drive around for little reason

If you don't get a license from the government, then subject yourself to numerous extra rules and get tracked by camera, how are you going to prove you have freedom? Maybe buying a lifted Ram will help.

You are Volunteered! (Score:2)

by walkerp1 ( 523460 )

I nominate you to always take the B-route so that I might squeeze out an extra 2 mph on the freeway. Don't worry, the long way is full of nature, and just smell that fresh breeze with guaranteed less carbon! No sir, you are not a loser.

I was driving up 101 once... (Score:2)

by commodore73 ( 967172 )

I was driving up the 101 once, north of San Francisco, maybe around San Rafael (not to far from Lucas Ranch). There was an accident or something on the freeway resulting in a huge pileup of vehicles. Google suggested an alternate route, but it must have suggested the same route to everyone. That route was a road with one lane on each side, so no good way to turn around, especially in traffic, and rural, so no intersections for maybe five or ten miles. Apparently, thousands of other vehicles had followed goo

What else can the algorithm suggest? (Score:2)

by Bruce66423 ( 1678196 )

Road A is blocked. Road B is the only alternative. So of course it will divert the cars onto road B. The degree of detailed understanding of the roads required to avoid this may be possible in the long term, but at the moment it's always going to happen.

induced demand is not a valid reason to not build (Score:3)

by 2TecTom ( 311314 )

Induced demand does not mean that building roads never reduces congestion; new capacity can provide substantial and sometimes lasting benefits. Rather, it means that traffic responds to changes in the cost and availability of road travel, just as traffic can decrease when road capacity is reduced through people changing routes, times, destinations, modes, or simply making fewer trips.

Commuting to/from work with google? (Score:3)

by 0xG ( 712423 )

If you use google to find your way to work and home, you have truly drunk the kool-aid.

Unethical (Score:2)

by martin-boundary ( 547041 )

Deliberate unauthorized tampering with lawful street traffic? Check.

Deliberate experimentation on unsuspecting humans? Check.

The Stanford University Institutional Review Board clearly dropped the ball on this one. Not entirely surprising since Stanford is Google's alma mater and I'll let you imagine what that means for board members.

There's a right way and a wrong way. The right way:

1) Ask humans for permission to experiment on them, before experimenting on them. No matter how minor the inconvenien

Google Maps are detached from reality (Score:3)

by devslash0 ( 4203435 )

Google has a fundamental problem with perception of which roads are equivalent.

It often sees rural 60mph roads as equivalent to highways where in reality they former are narrow, bendy, sometimes dangerous, and you can never so more than 30mph on them safely.

When I drive, I want the less hassle. I want to get from A to B with the least amount of thinking and stress. I would choose the road I know, or the road with the least number of turns over a road with even a 10-minute saving any time.

That's why I always turn down Google re-route suggestions. They are absolutely silly and detached from reality, and it annoys me to no extent that there is no global setting that aould allow you to disable automatic rerouting completely.

I'd like to be able to start the nav, look up the route, correct as need it and pin it so that it doesn't change mid way. Any modifications to the route should only be made on demand when I interact with the maps and tell it to try and re-route.

There's also something else that irks me considerably on Google Maps. In the UK it is illegal to interact with your phone in any way while driving. When Google re-routing pop-up appears, the default action after the timeout is "accept". This means that if I wanted to just follow the route I chose at the start of the journey, I'd have to break the law to turn the suggestion down.

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