FREMONT, Calif. (KGO) -- A lot of Bay Area drivers depend on their cellphone traffic apps to get where they are going.
Bay Area commuter Sierra Tavares says, "I love the Waze App. I mean I use it every single day. I commute from Manteca all the way to Los Gatos."
"I use Google Maps to get around and it definitely helps," says app user Kassandra Albarran.
But even some app fans admit the traffic information can sometimes backfire.
"I've noticed that it definitely tends to get people off on the same exit, causing more traffic," Albarran says.
It's been a year and a half since we first showed you the "don't trust your app" sign put up by the city of Fremont-- an early indicator of a problem that has only gotten more extreme.
"We think they are making things worse because they are sending vehicles and motorists into neighborhoods that they were not intended or designed for," said Noe Veloso, a Fremont Traffic Engineer.
The impact on Fremont neighborhoods is easy to see. When Interstate 680 slows down during evening rush hour the apps send traffic on alternate routes-- including Mission Boulevard. So it gets backed up and so do surrounding streets.
Fremont resident Deepal Panduia says, "There are so many commuters trying to get on to 680 and it's just horrible."
Now, state-of-the-art computer models appear to show the apps can have an even wider impact that goes beyond just a single neighborhood.
Alex Bayen is the director of UC Berkeley's Institute of Transportation Studies that created the computer traffic simulation-- speeding up what happens over a two hour period. The simulation compares traffic flow when 20 percent of drivers are using apps with traffic flow when no one is using apps.
"There is an accident. That accident obviously obstructs traffic. You can see the big piling up of traffic, but in the case of apps a lot of people choose the alternative routes as opposed to staying on the freeway," says Bayen.
After 45 minutes, the accident is removed, but the apps don't know right away. So they keep sending drivers off the freeway, backing up side roads and clogging on and off ramps many miles away.
As the incident plays out over two hours, the scenario "using apps" has worse long-term congestion and reduced traffic flow compared to the scenario with "no" apps.
Bayen says, "This problem is growing and this problem is not going to cure itself."
Bayen thinks the apps should be required to cooperate with government traffic agencies to improve traffic for the good of all, not just individual drivers. But that's not likely to happen any time soon, so Veloso says Fremont and many other cities are fighting back.
Fremont traffic engineers watch the apps during peak traffic times to see where they are routing drivers. On the day ABC7 News was visiting, Veloso showed us how the Waze app was sending drivers off I680 on to residential streets and right by Mission San Jose High School. Veloso pointed out the app was sending drivers near a school at about three o'clock, just when students get out of class and there is already significant traffic.
Another test showed Google Maps telling commuters they could turn their 32-minute drive into a 28-minute drive by getting off the freeway and driving through Fremont.
"Google Maps and Waze are sending people off the freeway for a travel time savings of only four minutes, but it's impacting a large part of our community," Veloso said.
Fremont has added "no turn" signs and more stop signs to discourage cut-through traffic. But as things get better in one neighborhood-- the apps just route drivers to another one. So in March engineers expanded the use of a tougher tactic.
"If you exit the freeway and are looking to save time off your commute by using our residential streets, we are going to punish you by delaying you at our traffic signals," said Veloso.
During the afternoon commute red lights on parts of Mission Boulevard last a lot longer than usual.
"I had no idea, no idea. Thanks for letting me know that," said commuter Don Nelson.
Engineers are still tweaking the exact timing.
"To try to find the right balance of reducing the cut-through traffic and not impacting our residents significantly," said Veloso.
Early indications are the number of drivers cutting through Fremont is down. But we still found plenty of backed up traffic and not every commuter willing to change their habits.
Livermore resident Maenya Vlasoff said, "Even though they slowed down the traffic lights, this way is a lot faster for me."
Both Waze and Google Maps are owned by Google. Neither would do an on camera interview, but both sent statements:
Statement from Waze:
Waze was designed to thoughtfully and carefully reduce traffic by directing drivers away from places that are already congested-not to send everyone down the same route, which would make traffic worse. We are entirely committed to partnering with cities and transit authorities to solve shared transportation challenges, as evidenced by our work with more than 800 partners globally through our Connected Citizens Program which shares real-time anonymous road data and traffic management tools. The root of the problem is too many cars on the road, so we recently launched Waze Carpool which encourages drivers and riders headed in the same direction to carpool together. Waze Carpool is a solution that can reduce the number of cars on the roads now, and if we all work together, we can make traffic history.
Statement from Google:
Google Maps strives to accurately model and reflect the real world. Municipalities and agencies responsible for managing roads and reducing traffic are free to take measures according to their individual needs (e.g. speed humps, changing speed limits, adding traffic lights). Google Maps will then strive to reflect that reality completely and accurately in our map model. And our automated routing optimization algorithm will inherently take those parameters into account in every route created in Google Maps.
Bay Area transportation experts say apps may make traffic worse
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