The back streets crisscrossing San Francisco's Glen Park neighborhood are narrow and winding, riddled with blind curves and lined with parked cars. Residents say a lot more cars have been attempting to navigate some of those tight turns in recent years.

This pricey urban village, one of the hottest real estate markets in the city, was once a collection of cottages linked by paved-over goat paths. The streets are so narrow, many shrink to a single lane if cars are parked on either side.

They were never meant to handle more than residential traffic, yet popular mobile mapping apps such as Google Maps, Apple Maps and Waze appear to be routing motorists and ride-share drivers up the crooked alleys in droves.

One side street in particular has become a flashpoint for traffic congestion — Miguel Street.

At a blind curve between Beacon and Bemis streets, Miguel narrows to 10 feet wide, allowing room for only one car to pass.

Gayle Laird, who has lived on Miguel since 2013, says drivers coming from both directions will often meet at the blind corner, "their brakes screeching."

"There will be a standup," Laird says. "It will take 15 or 20 minutes and people have to get out of their cars to talk and figure out what to do and who needs to back up."

Because the road is cramped and a line of cars sometimes trails on either side, backing up isn't always easy.

"Cars often pull into our driveway and then back out to allow other cars to get by," says Brian Runser, another Miguel Street resident. "In some cases careless drivers back into parked cars.

In the most extreme cases, accidents occur. "I have heard them happening and run out and see the aftermath," Laird says. "A neighbor says there was a pretty big one a couple months ago."

ALSO, Uber, Lyft cars have heavy impact on SF streets, study finds

Laird and Runser both have friends who say they have been routed by apps to Miguel Street after they exit Interstate 280 to Glen Park. It's an alternative to taking Bosworth Street to O'Shaugnessy Boulevard.

Google Maps

"It's a shortcut from Mission to Market," Laird says. "You take Miguel to Diamond and then get onto Market."

Runser said many of the cars cutting through the neighborhood are ride-share drivers.

"It's hard to provide concrete evidence, but I can say that during commuting hours especially almost half the cars driving down Miguel Street look to have a Lyft or Uber symbol on them," he said.

VIDEO: A typical morning on Miguel Street, footage taken May 11

SFGATE visited Miguel Street at about 9 a.m. on a Friday in May, and indeed a steady stream of traffic was traveling from the 280 freeway and up and over the hill to the west side of the city via Miguel. We captured a brief backup in the video above.

***

The problem is not limited to Glen Park or even San Francisco. Side streets in cities across the nation are seeing dramatic increases in traffic, says Alexandre Bayen, the director of UC Berkeley's Institute of Transportation Studies.

Bayen says his research shows in some cases the "fastest route" is now no longer the best option because too many people are using it. As a result, neighborhoods are unnecessarily being interrupted.

"This is happening everywhere," says Bayen, "We're trying to catalog all the places it's happening. It's like cancer, and happening really fast."

Bayen explains that the problems with the apps arise with their inability to communicate with one another and to predict and forecast traffic with precision.

"These apps are supposedly choosing routes based on traffic time, but they don't precompute your impact on traffic," Bayen says. "In order to do the right thing, these apps would have to anticipate their impact on the network. But this isn't a single player game. Company A doesn't know what Company B is doing. Say Company A is sending all their drivers on one route, and they don't know Company B is using the same route."

In a recent talk, Bayen gave the example of an accident that blocks a lane on a freeway. Drivers turn to their apps to find a detour and are routed to the same exit, which suddenly can't handle the increased traffic.

"[The apps] don't even know about this because they're working on fixed, simple timing plans," he said.

Transportation network companies (TNCs) such as Uber and Lyft who have their own routing software identifying the fastest routes and who are also using navigation apps, make the situation worse.

The San Francisco Treasurer's Office estimates a total 45,000 Uber and Lyft drivers may operate in the city, with 5,700 vehicles operating on streets during the peak period on a weekday and over 6,500 at the peak on Fridays.

On a typical weekday TNCs make 170,000 vehicle trips, approximately 12 times the number of taxi trips, according to the city's research. In terms of intra-San Francisco vehicle trips, more than 1 out of every 6 is by ride-share car.

Lyft argues that TNCs are taking cars off the road and points out that while there may be more ride share drivers on the road, their research shows that their passengers are using their (own vehicles?) 53 percent less. What's more, in San Francisco, Lyft says nearly half of all its passengers are using the carpool "line" service.

"Lyft was founded to help solve [the problem of traffic] by increasing utilization of cars that are on the road and getting more people into fewer of them in general," a statement from Lyft reads.

SFGATE reached out to Uber for comment and didn't receive a response.

ALSO, SFO looks to hike fees for Uber, Lyft rides

****

One of the more popular navigation programs, Google Maps says it "strives to accurately model and reflect the real world."

In response to a request for comment, Google Maps released a statement saying, "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."

Waze, another navigation app owned by Google, says it will make the same changes to its map though removing a public street from a map isn't an option.

"The Waze map reflects cities as they are, not the way someone wishes them to be," Waze CEO Noam Bardin writes in a Medium article. "If a road is public, it will be used within reason to help spread 'knots' of congestion throughout open spaces of the grid of a city."

The City of San Francisco has taken several steps to improve safety and address neighbor's concerns on Miguel Street, and in the past two years they've reduced the speed limit to 15 mph, installed signage with notification of the blind spot and painted edge lines to help motorist navigate the narrow street correctly, according to Paul Rose, a spokesperson with the S.F. Municipal Transportation Agency. Most recently, in October 2017, a stop sign was installed at the corner of Miguel and Beacon.

"We did briefly explore options to make this stretch one-way, but there was no interest from the neighborhood," Rose wrote in an email.

The changes are a step in the right direction, but the congestion clogging Miguel is still causing havoc.

"Despite the addition of the 15 mph signs and the white lines on Miguel, I have personally seen no improvement in the traffic situation on Miguel," wrote one resident in a recent NextDoor thread. " My husband's car has been hit three times in two months. The neighbor across the street has had his car hit twice recently. My car was hit for the fourth time a few months ago, causing $1200 in damage."

Part of the problem might be the overall design of Glen Park's network of streets. Woody LaBounty, a San Francisco historian who founded the Western Neighborhoods Project, explains Glen Park's streets were laid out in the late 1800s when the neighborhood was being developed to house the city's working class.

"Glen Park was laid out parsimoniously," LaBounty explains. "The developers maximized the lots. They were basically paving over old goat paths and building small cottages for people who worked on the railed (?), at the dairy. Now, these little houses have giant SUVs."

The streets in neighboring Ingleside, he points out, are much wider as the developer wanted a "fancy, upper-class neighborhood."

San Francisco police Capt. Jack Hart, who joined the Ingleside Station six months ago, says he's fully aware Miguel Street continues to receive an overload of traffic and has received seven personal complaints about the street since Glen Park became part of his territory. On a number of occasions, he has sent officers in cars and on bikes to ensure motorists are obeying the speed limit.

Hart says he doesn't have any proof that mapping apps are sending motorists on Miguel but he has a hunch they might be behind it.

"How are people even finding this little street?" Hart says. "My grandparents lived on Chenery and before all of this, even if you said Miguel, I wouldn't have known where it is. Efficient doesn't necessarily mean that the roads have the capacity to do what the little blue lines on maps tell you to do."