"Y" Intersection of Santa Cruz/Alameda - Safety

"Y" Intersection Information Section

The "Y" intersection of Santa Cruz Ave & Alameda de las Pulgas is one of the most dangerous intersections in all of county. The current design supports skewed approaches, not recommended by Federal Highway Administration guidelines. It is oriented to high speed, something that the community wants to avoid by instead having a lower speed road design where cars naturally drive more slowly and safely. In this webpage section please explore the various links to gain more information on getting a better design, identifying the safety issues, and read what fellow community members have voiced.

There is a FAQ section to start to answer questions: If you have a question that is not listed or a concern/idea not included, please leave a "Comment" in the FAQ, or send an email to Safety@UnivPark.org.

This is an especially important section for our community, our fellow neighbors to be engaged. County has decided to ignore FHWA and the Berkeley Pedestrian Safety Assessment that points to a safer design and instead base changes on the same basic and dangerous configuration we currently have. We all use this key segment of the corridor - it needs to have the dangerous design removed and a safe design in place.

The content here changes and grows over time, based on comments and new information resoures -- It is a Work In Progress.

"Y" Intersection of Santa Cruz & Alameda

Related Information

Below is a set of interactive comparisons of the 3 Alternatives presented on Jan 30th and the community's Safety Option #10.5. The community option 10.5 substatially improves the intersection by simplifing the design, reducing speed, reducing conflict areas, and reducing the size of the intersection by 30+%. Areas in brown and light brown could be greenery or other taffic calming features - the darker gray areas are basically recovered roadway areas that provide safety buffers by the redesign.

Frequently Asked Questions & Answers

What is not addressed by the County design for the Y?

Northbound Santa Cruz Ave - Critical Safety Issues

The Santa Cruz Ave/Alameda de las Pulgas "Y" intersection design, both the current and the plan County is promoting, are plagued with serious safety issues:

Creates an unsafe situation for residents to enter/exit
Unsafe for pedestrians to cross due to angled crosswalks and crosswalks that are excessively long
Skignificantly skewed intersection
Blind corner putting pedestrians at high risk
Too many confusing traffic signals that are unclear
High speed 'slip' curve designed for 50 mph
High safety risk to cyclists
... see the FAQ on "What are the safety issues at the Y"

Unfortunately, the 'new' County plan does not resolve these issues; for instance, to cross Alameda on the north crossing currently means the pedestrian has to walk the equivalent of 9 traffic lanes due to angle and poor design. To cross under the new design the pedestrian has, to walk the equivelent of 12 traffic lanes (33% longer!). In contrast, under the Community safety option 10.5 design, the pedestrian crosses just 2 lanes, meaning the pedestrian is in the intersection for about a quarter of the time.

Another example is that the high speed slip turn that not only encourages speeding but also creates a high risk to pedestrians and residents at the "Y". Traffic engineers have recommended its replacement by a 25 mph turn that elemenates the severe skew of the intersection (in concert with traffic calming goals for improved safety).

Since the County's 'new' design is using the exact same basic intersection design as what we currently have, it can't address the many issues that currently exist. Compared to Safety Option 10.5 that does address all of the safety issues, the County's new design seems like a lot of money to spin wheels and not significantly gain on safety and leave our pedestrians and residents with undue risk.

To view an interactive comparison of all the designs for the "Y", please view the Pro-vs-Con discussion.

What are the safety issues at the Y?

Y Intersection - Santa Cruz/Alameda

The Y intersection is one of the most dangerous intersections in all San Mateo County. Most of the issues here relate to a very poor design and configuration, including serious safety issues for pedestrians, residents, and cyclists. There are many safety issues, here is a short list of some of the many that are documented for this intersection:

Speeding is a major problem
Poor visibility between motorists & pedestrians
Poor visibility between motorists & residents
High speed NB slip lane
No viable ADA sidewalks/pathways
No bike lanes or cyclist protection
Skewed intersections
Crosswalks unsafe and extremely long angled
Confusing traffic lights - too many traffic lights
County's inability to fix major traffic signal conflict between pedestrians and motorists
Blind corners
Extremely wide and confusing intersection
Unsafe distance between motorists and pedestrians
No stop-yield lines to provide safety buffer between motorists and crosswalks
No Traffic Calming elements to provide natural speed reduction (greenery, narrower lanes, medians, islands, etc)

In a Nut Shell: (See Pro-vs-Con discussion)

Virtually all of the problems at the Y intersection are due to its ill thought out basic design. The design goes against the Federal Highway Guidelines that identify Skewed intersections should be changed to be 90° angles for the safety of all, including pedestrians. The Pedestrian Safety Assessment (Berkeley engineers) that was submitted to County underscored the same recommendation.

Currently the County is proposing keeping the same skewed design. That is a problem. The community design proposal (Safety Option #10.5), which incorporates the engineering recommendations of both FHWA and Berkeley. With that redesign, skewed approaches are eliminated without impact of traffic volume. All of the documented safety issues pertaining to this intersection are addressed and solved, including a natural and proven to have motorist drive slower and saner.

We need a new design that actually solves the safety issues and not double down on the same dangerous current design that has so many ingrained safety issues. To view an interactive comparison of all the designs for the "Y", please view the Pro-vs-Con discussion.

Why the 90 Day Safety Trial?

County, at the urging of our community, agreed to implement the temporary trial to test the impact of the several important safety improvements gained by proposed changes. By creating a temporary road configuration to test the key tenants of the proposed safety improvements, to address several of the very serious and dangerous intersection design issues.

In short, the trial will provide many safety improvements and gather traffic data to see the effectiveness of the improvements:

Eliminates over 5,500 lane changes per day
Moves the traffic lane away from the adjacent sidewalk, providing safe pedestrian buffer
Eliminates the primary cause of the chronic red light running at this intersection
Provides local residents a reprieve from traffic to safely access their driveways
Shortens a dangerous and long crosswalk
Provides traffic calming to help slow excessive speeding (a 1st initial step in addressing this)
Eliminates the chaotic traffic flow at this NB intersection, providing cyclists and motorists a calmer flow
Slip Lane configuration eliminates the tendency of motorists cutting in to the shoulder/park lane
Traffic lights at this intersection will be 'normal', behaving as all other intersections in the area
Removes that short 3rd lane that was added just prior to the intersection keeping only the 2 primary NB lanes.

During the Safety Trial, Count plans on monitoring of traffic flow and speed. The key safety gains will be observed and monitored. Some of evaluation criteria is:

By keeping 2 lanes of traffic and eliminating a short 3rd lane, evaluate the impact on NB traffic
Evaluate the use of dedicated NB lanes, one each for Alameda and Santa Cruz
Determine if the normalized traffic light is achieving the safety goals for Santa Cruz Ave residents
Determine if the NB traffic flow to and through the Y intersection is calmer and observe if drivers are less distracted

Click this email link: Email County - it will automatically address email to Supervisor Don Horsely, County Manager Mike Callagy, Public Works Jim Porter, and our Safety email addresses.

What are addressed by the Safety Trial at the Y?

The Santa Cruz Ave/Alameda de las Pulgas "Y" intersection is one of the most dangerous intersections in San Mateo County. Issues of speeding traffic, red light running, danger to pedestrians and residents, and a road design that required 6,000 vehicles per day to change lanes in to a 105' 3rd lane. That forcing of vehicles to change lanes created a dangerous and chaotic roadway with distracted drivers (trying to change lanes or dodge cars that were) where cyclists were placed in a no-mans land and at very high risk. Furthermore, that 3rd lane pushed all of that chaotic traffic up against the sidewalk endangering pedestrians and a long history of cars crashing into properties.

All of this is compounded by other unsafe conditions at the Y including long angled crosswalks, an almost always green - freeway onramp like - slip lane, virtually no cyclists safety guidance, and conditions that inspired aggressive and speeding motorists.

Pros & Cons - Santa Cruz/Alameda Y Intersection

A community design for the Y - Safer and naturally slower traffic

There is a big difference in keeping the same design that has given us the most dangerous intersection in all of County and insisting on a redesign that has all of the safety issues addressed and with traffic calmiing engineering that provides for a natural way for traffiic to flow slower and saner. Are there Pros vs Cons? Explore the conversation on at Santa Cruz/Alameda Y Intersection - Pros vs Cons.

Other Alternatives

In 2017 San Mateo County provided 4 alternatives for the Santa Cruz/Alameda corridor. Most of those were rejected as they did not address the safety problems and had serious design issues. In Jan 2020, County provided 3 alternatives. Alternative A was rejected because it was basically a do nothing alternative and did not address improved safety. Alternative B was also not selected. It had unanswered traffic mitigation issues and also lacked support for addressing key safety issues.

County narrowed it down now to their Alternative C, even though that also has design issues and lacks support for key safety measures. Hopefully the will consider our Community Safety Option 10.5 that does address the safety issues and is designed to limit speeding. See the comparison between C and 10.5.

Alt -C -vs- Community 10.5

Click title for more detailed view with pros-cons

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