Like many problems plaguing modern life, traffic is a daily nuisance that many are trying to fix with technology. From Uber and Lyft to autonomous vehicles to navigation apps such as Waze, tech firms keep searching for ways to deliver us from our daily commute.

One California town near Silicon Valley, Los Altos Hills, decided that tech was both the cause and solution to its traffic problems. It learned, however, that while apps come and go, regional transportation planning (or lack thereof) has a much longer lifespan.

The problem Los Altos Hills has with traffic is due, in a significant part, to the fact that it’s not set up for excessive traffic. Located in Santa Clara County, Los Altos Hills contains two of the wealthiest zip codes in the country, and has no commercial zoning. The residential enclave is basically composed of a series of smaller, winding roads connecting expensive homes. So when rush hour traffic from I-280—which bisects the town, and decreases from four to three lanes on the southbound side just outside the town limits —began encroaching on these residential streets over the last few years, residents clamored for action.

A solution local government agreed on, according to public works director and city engineer Allen Chen, was to contact Waze. They assumed Waze-directed traffic had steered an excessive number gridlocked commuters onto side streets. Earlier this April, they contacted the service via its connected citizens platform, and after discovering they couldn’t get streets taken off the mapping service, declared certain streets were closed to thru traffic, installed street signs, and got Waze to mark them as such on the mapping app.

The navigation app, which delivers directions to users in real time, often redirects drivers from main road and highways to side streets in small towns, based on on-the-spot reports of traffic jams and accidents from other users. These Waze-created traffic disruptions have become issues in cities and towns across the country, especially suburban roadways designed for scenic rides and residential splendor (as opposed to efficient urban grid patterns). Residents and local governments have tried to game the system, including, as Slate reports, a man in Takoma Park, Maryland, who reported fake accidents and traffic jams.

Waze does have ways for local governments to reach out and interact, and can update its map to reflect new municipal laws. In addition, its community outreach program has been successful for other nearby cities, such as Fremont, California, which worked with the app to develop “countermeasures” for increased thru traffic, such as ramp metering and turn restrictions.

But as Chen and Los Altos Hills residents have discovered, even when Waze responds, it won’t fix the bigger issue of regional traffic congestion, which has become a crisis in Silicon Valley, with more local drivers enduring supercommutes of 90 minutes of more than in LA.

According to Chen, the city hasn’t seen a decrease in traffic since adding the signs, and also hasn’t issued any tickets for those breaking the rules. Chen said any difference in traffic is barely noticeable.

From his perspective, the bigger issue is the local highways. He’s asked Caltrans, California’s department of transportation, to re-stripe the highway to add a fourth lane. They just responded that they won’t be doing that anytime soon. He also said that for the most part, adding “no thru traffic” signs is a hollow gesture; to determine who does and doesn’t have business in a neighborhood would require extensive stops by police.

The true issue is the bottleneck of cars and commuters going into and out of Silicon Valley. Technology may slightly disperse the flow of traffic here or there, but without better roads (or more public transit options), it’s just making a slight dent in a much larger issue. Tech may help some find a work around. But without major infrastructure and planning investments, the larger issue won’t be fixed by a clever algorithm.

As Chen put it, once congestion causes overflow traffic, “it’s just like a water spout – it goes everywhere.”