On a hot Saturday it starts at the Highway 17/Highway 9 cloverleaf. The on-ramps and off-ramps sit close together, so merging traffic slows the freeway. Once Highway 17 slows down, navigation apps that route by travel time start sending drivers onto Winchester Boulevard, University Avenue and Los Gatos Boulevard. When those roads fill up, the apps push traffic deeper into the neighborhoods behind them, looking for any faster path.
Udit Molakatalla, the traffic engineer from DKS Associates working on the interchange project, described that cascade to the Los Gatos Town Council at a September 15 study session. It explains something the Town has spent years learning the hard way. Beach traffic on a Los Gatos side street is mostly a freeway problem, and the apps undo nearly every fix applied at the street level.
How a slow freeway turns into a slow University Avenue
The size of the problem shows up in two figures VTA presented. In 2022 VTA data, about 24% of the cars on Highway 17 cut through Los Gatos during peak weekend commute hours to get around the bottleneck. On a typical weekday the interchange moves about 3,900 vehicles per hour. On a beach weekend that drops to roughly 3,300.
So the interchange loses capacity on exactly the days demand is highest. VTA project manager Chris Lilley told the Council that weekends and heat waves bring the heaviest traffic. Those are the days drivers leave the freeway, and those are the days University Avenue and Winchester Boulevard back up.
The Town's own explanation, in its Weekend Cut-Through Traffic FAQ, follows the same sequence:
- Traffic builds on one route, and the mapping programs work out an alternate.
- Early in the buildup, the first street affected gets some relief.
- As volumes keep climbing, the alternates fill too.
- In the end, every route is affected.
The FAQ also says much of the cut-through traffic enters town from smaller streets, not from the freeway exits. That matters for the fixes below.
Every street-level fix got routed around
The FAQ, last revised in August 2026, is frank about what the Town has tried. Staff describe the late 2010s and early 2020s as a period of trial and error and pilot projects, and conclude that "None of those solutions solved the problem."
Each attempt ran into the same cascade.
Closing South Santa Cruz Avenue at Wood Road
The pilot closure moved the impact to streets on the east side of Los Gatos Boulevard near Kennedy Road. It also added traffic to Highway 9, which made it very hard to drive downtown to local businesses. The Town is not repeating it. A roundabout at the same spot was dropped years ago after talks with Caltrans and because of its high cost.
Making North Santa Cruz Avenue one-way
The apps sent traffic onto side roads and then back toward downtown, because every driver still needs the same on-ramps. According to the Town, the pilot made the bottleneck bigger at the closed intersections and cut off downtown parking for customers.
Turn restrictions on Tait, Massol and Ridgecrest
Almond Grove residents were split on this idea, according to past feedback, and the Town does not plan to do it again.
Asking the apps to cooperate
The Town told Apple Maps, Google and others about its neighborhood street designations. The FAQ says the companies did not want to change their algorithms any further, and that if one app held back, another might use that as a competitive edge. The major apps showing cut-through routes are Waze, Google Maps, TomTom, Inrix and Apple Maps.
The ideas the Town cannot legally use
"Local Traffic Only" signs are advisory. The Los Gatos Monte Sereno Police Department can't enforce them, and the apps ignore them. Closing roads to everyone but residents is barred by California Vehicle Code Section 21101.6. Tolls on local streets aren't allowed under state rules. The freeway ramps at Highway 9 and Lark Avenue belong to Caltrans, and Caltrans has said it won't consider closing them.
More police would not change the picture much either. Controlling a single intersection often takes two officers, about a third of the officers on duty. Even then, the FAQ notes, traffic is often so heavy that there's nowhere to move the cars.
What still runs on a summer Saturday
One measure has lasted. From 10 a.m. to 3 p.m. on Saturdays, drivers can't turn right onto North Santa Cruz Avenue from Alemendra, Bachman and Nicholson. The goal is to keep cut-through traffic out of Almond Grove, the area bounded by Highway 9, Santa Cruz Avenue, Massol Avenue and Broadway. The Town says some mapping apps build the restriction into their routing and others don't, and staff keep watching the apps.
The Town has also put its own changeable message boards near the highways with stay-on-the-freeway messages. Caltrans has declined to run that message on its permanent signs, and staff were discussing with Caltrans whether to use the Town boards again. The FAQ doesn't say whether that happened in summer 2026.
To report a traffic problem, use the Town's MyLosGatos311 app. The FAQ also points out that an officer has to see a violation in person to write a citation.
Staff are now building a computer model of the town's road network to test possible solutions before trying them. The same model will be used to study emergency evacuation needs and how beach traffic could affect them. The Town expects the modeling to be done in 2027.
Why the redesign targets the freeway
The State Route 17 Corridor Congestion Relief Project is a joint effort of VTA, the Town and Caltrans. It starts from the same idea as the FAQ. If the apps send traffic down whatever route is fastest, make Highway 17 the fastest route again. Molakatalla told the Council the goal is to reverse the cascade so the apps send drivers back to the freeway.
The plan replaces the aging cloverleaf with a "spread diamond" design. It adds a third lane in each direction of Highway 17 between Lark Avenue and the interchange, ramp meters on both on-ramps, and a wider six-lane overcrossing in place of the current one. The northbound diagonal on-ramp gets a high-occupancy vehicle lane meant to stop drivers from jumping the line, which feeds cut-through traffic.
Lilley described three ways it is meant to pull cars off local streets:
- More room before the breaking point. The extra lanes let traffic back up farther from the interchange before drivers give up and exit.
- Closing the throughput gap. The new design should narrow the difference between the 3,900 vehicles per hour on weekdays and the roughly 3,300 on beach weekends.
- Metering. Ramp meters give operators more control over how much traffic enters the freeway at once.
What it costs Highway 9 and gives bikes and pedestrians
The redesign has trade-offs, and VTA named them. Today's free-flowing ramps would become intersections controlled by traffic lights. Lilley acknowledged that this will add modest travel time along Highway 9. The two new signals go at the realigned ramp intersections with Highway 9. A 2022 Caltrans notice says the existing signals at Alberto Way and University Avenue would be upgraded and linked together.
The project's traffic study looked at about 19 nearby intersections. Lilley said not all of them will improve, and the two new signalized intersections will see the most added delay.
The signals are a deliberate trade for safer walking and biking, especially with Los Gatos High School nearby. The interchange now scores a 4 on the Bicycle Level of Traffic Stress scale, the worst rating, described as "not suitable for children or most adults." The redesign is projected to bring it to a 1, rated "comfortable for all ages and abilities including children." The plan adds wider sidewalks, buffered bike lanes and a new Los Gatos Creek Trail connection, which the Town will provide.
"What we're trying to accomplish is to eliminate State Route 17 as a barrier to active transportation," Lilley said.
The calendar from here
The next step is public comment. The project is going through both state and federal environmental review, and the Town staff report for the September 15 session says a Draft Environmental Impact Report/Environmental Assessment was being finalized for public release and comment. The Town's September 11 newsletter said that release was expected "later this fall." No date has been announced.
VTA's posted schedule:
- 2021 to 2027: environmental approval
- 2027 to 2029: design and engineering
- 2029 to 2031: construction
The estimated cost has risen to $178 million, $16 million more than the 2025 estimate. Lilley said about $13.2 million in Measure B funds plus about $1.4 million already committed by the Town should come close to covering the final design phase. Construction funding is a separate question. The 2031 finish is the target "if all goes according to plan," according to the Los Gatan's account of the session.
That leaves about five more beach seasons with the current setup. For those summers, the Town's advice is the same as before. Make weekend car trips through town earlier in the morning or later in the evening, and on mild days walk or bike the town's trails and bike paths for errands, dining and shopping.
Brian grew up in Los Gatos, and the Brian Flack Team follows projects like the Highway 17/9 interchange because they change how a street works on a Saturday. If you live along University Avenue, Winchester Boulevard or in Almond Grove and want to talk through what the redesign could mean for your block, or want a current read on your home's value along the way, get your instant home valuation and we'll take it from there.
