South Half of “Y” Intersection

Since the “Y” intersection of Santa Cruz & Alameda is such a complex area, we are splitting the website’s discussion up into a north half and this webpage for the south half.

The following based on the new February 2024 design that County contractors provided. For this southern portion of the Y a slight improvement of keeping some of the parking buffer was included, there hasn’t been much else improved safety wise from prior plans, nor from what the intersection looked like 15 years ago (See comparison here). Many of the same problems remain unaddressed.

Modified Plan from DPW — Feb 2024

In fact, the county contractors in this February 2024 update, have actually thrown out the safety gains the community accomplished in 2018, where back in 2018 we had implemented changes to the width of the roadway, added better safety buffer for residents and pedestrians. We eliminated the dangerous lane shift that had been there and that was causing so much chaos and many accidents. Unfortunately virtually all those safety advances have been removed and the old problem design elements re-instated.

Read the bullet points in the illustration to gain an understanding of issues

Community Safety Alternative:

The illustration below shows reasonable suggestions to address safety. It greatly increases residential safety by providing a needed buffer to for safe(r) ingress/egress for driveways. It provides short crosswalks. It reduces the width of the intersection. There are other noted safety issues addressed:

The emphasis of the community is safety. Safety for residents to enter/exit their driveways. Safety for pedestrians to be buffered from traffic when using the sidewalk and when crossing. Safety for cyclists to have a calmer, safer, route through the intersection for all directions.

Motorists too have improved safety by a calmer flow of traffic and a less confusing intersection. Improved sight lines provide better visual contact with pedestrians (and cyclists). Rather than mismatched traffic paths, the traffic lanes follow the natural geography of the intersection curves as would be expected by motorists.

Animated to Help Visualize Issues and Solutions

The illustration here is an animated toggle between the County consultants Feb 2024 design and our community suggestions as reasonable fixes. The animation will toggle quickly between the two graphics to help show changes, the animation then pauses for about 10 seconds to show each illustration with notes.


Animated comparison of designs: 15 years ago vs Feb 2024

The following animation toggles between what the intersection looked like 15+ years ago and the newest design from County contractors. The main focus of this illustration is to compare the layout by contrasting crosswalk and median placement. To better visualize this focus, roadway lane definitions are muted. You will notice that the issues listed in the illustration remain unaddressed. Note also that the base – fundamental design is the same!

Background and Overview

Three decades ago, this intersection was part of an effort to have an ‘Expressway’ style design to flow double lane traffic at high speeds through the neighborhoods to and from north and northwest destinations. The “Y” intersection splits traffic volume fairly evenly, with a daily volume of 5,000 cars using northbound Santa Cruz and 5,000 using northbound Alameda. The design is referred to by traffic engineers as ‘motorist centric’. This has resulted in County DPW acknowledging that the Y intersection has been one of the most dangerous intersections in County.

It has major design issues and dangerous elements, including:

The biggest problem with the “Y” intersection is the design itself: It has a ‘skewed’ approach, something that the FHWA, NACTO, and other engineering organizations highly recommend changing to be a simple 90° degree approach. Despite a major Pedestrian Safety Study of this intersection conducted for County that highly recommends fixing the skewed approach, it doesn’t look like County contractors will address this.

One of the major problems created by Y’s skewed design, is its high speed NB Santa Cruz turn that accommodates 50+ mph speeds. The Y’s lack of pedestrian safety, both along the sidewalks and the crosswalks. For example, the crosswalk to cross Santa Cruz is angled, causing sight line problems between pedestrians and motorists. The crosswalk is at least 23% longer than needed. The intersection has a high speed turn is a problem and it seems most in the community would rather a turn based on the 25 MPH speed limit.

  • Sightline issues at corners and along sidewalks
  • Intersection is extremely large
  • Historically high accident rate
  • Speeding traffic – High speed turns
  • Residential properties and houses have been hit by vehicles
  • Pedestrian safety was practically non-existent in the design — a double problem for people with disabilities
  • Intersection has a Motorist Centric design
  • No safety for cyclists
  • Traffic signal lights are confusing and complex
  • No provisions were provided for residents to safely use their driveways
  • Traffic lanes flowing right next to sidewalks – no provision for:
    • Trash and recyclingpickup
    • Package delivery and Service utility vehicles
    • Safety buffer for pedestrians
    • Safe sight lines

Rather than replace this dangerous and problem riddled design with an intersection recommended by FHWA, NACTO, and other traffic safety design organizations, county contractors seemed to be stuck with the old expressway mentality (see comparison). We really need to get past this motorist centric thinking and deliver a design based on safety objectives:

  • Keep traffic speeds in line with our 25 mph speed limit – no 50 mph turns
  • Will reduce motorist confusion and improve awareness of pedestrians and cyclists
  • Have short crosswalks – reduce time people are in roadway – reduce traffic signal time
  • Remove obstacles in sidewalks and roadways
  • Make the intersection usable by people with disabilities
  • Provides safety for residents accessing and exiting their properties
  • Remove the design aspects the confuse motorists or are unfamiliar or unexpected
  • Simplified intersection – promotes less conflict and confusion

Serious Issues with County’s Newest Feb 2024 Design Plan


Three decades ago, this intersection was part of an effort to have an ‘Expressway’ style design to flow double lane traffic at high speeds through the neighborhoods to and from north and northwest destinations. The “Y” intersection splits traffic volume fairly evenly, with a daily volume of 5,000 cars using northbound Santa Cruz and 5,000 using northbound Alameda.

Rather than replace this dangerous and problem riddled design with an intersection design based on safety objectives: Designed for 25 mph speeds, a residential neighborhood ambience, with traffic calming elements, short crosswalks, and prioritizing residential, pedestrian, and cyclists safety, County contractors have instead stayed with the same dangerous intersection base design. Compare the ‘old’ intersection to this new design ( here ) and notice that there is almost no fundamental difference between the two. Dangerous and serious issues remain, and will remain for the next 30 years unless county contractors address these issues now — virtually all issues can be addressed with minimal cost, if any.

The contractors have kept the same high speed approaches, including the NB Santa Cruz slip lane design that supports 50 mph speeds and unfortunately motorists take this turn at high speeds. County contractors continue to emphasizes a motorist centric design at the expense of safety for other users. Under the County design, pedestrian and cyclists are at significantly higher risk. People with disabilities will have a difficult time using the intersection. Residents are at increased risk due to the removal of buffer space between traffic and their property, thus making it even more dangerous then they currently experience when exiting or entering their driveways. A serious step backwards in safety.

The last time County designed the roadway for West Menlo Park, specifically the Santa Cruz/Alameda traffic corridor between Sand Hill Rd and Avy Ave (see intro map), the plan was the creation of an expressway style road to move traffic quickly through this short area of our neighborhood.  At that time no thought materialized for bicycle safety.   No thought appears to have gone in to pedestrian safety.  Residents were left with dangerous issues when entering/exiting their properties. 

Our current roadway design was not a success, as is shown by the corridor’s long history of frequent traffic accidents, injuries AND deaths.  Many in the community don’t feel this roadway design is safe. That lack of safety has caused some to move away and others to live in constant unease.  Add to this a lack of effective safety action over the least 18 years by County. County could have mitigated some of the poor design and the safety issues, yet over the last 18 years, county has been reluctant to do effective action that has been identified to them.

Where the County Design Fails: 

What has County contractors delivered as a re-design at the “Y” intersection?  A continuation of the same intersection footprint.  Basically the same intersection with different lipstick💄.   Just the opposite of what we need. We wanted greatly improved safety for peds, cyclists, residents and we wanted traffic to flow at lower safer speeds, not keep 50+mph turns and extremely long crosswalks.

Review the following observations from County’s newest design and see which of these points make reasonable sense:

  • County removes the equivalent of 3 lanes from the Y intersection width, yet the new design creates an even wider intersection. Why is this excessive intersection width necessary? Why make it even wider?
  • The ‘new’ design is based on a design that was created 50 years ago for an expressway style road with upward speeds of 50+ mph?  Why not a simpler, slower, smaller intersection, designed for 25 mph and for a residential neighborhood?
  • Virtually all traffic engineering organizations, including FHWA and NACTO recommend correcting skewed intersections to be 90° perpendicular, as was also recommended by the Pedestrian Safety Assessment study done for county for this intersection. Why is the intersection then still basically the same problematic and dangerous layout?
  • The new design impedes emergency response, blocks access to residential driveways, and creates cycling paths that are dangerous and significantly less safe than alternatives?
  • This list could go on.  Its purpose here is to provide an insight into the need to modify and correct the “Y” intersection design.  It doesn’t make sense to ignore community input and spend millions of dollars to double down on a proven to be poor and dangerous intersection design that has so many safety issues. It doesn’t make sense to end up with a ‘new’ design that makes it more dangerous for residents and pedestrians. It doesn’t make sense to have a bike route that is significantly less safe than alternative options.

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Please add your thoughts, concerns, feedback, and questions by using the Reply comment form below. All comments go through an approval step, meant to keep spam comments in check. Please be constructive with your comments and respectful.

Authored Mar 2024,

5 thoughts on “South Half of “Y” Intersection”
  1. For this portion of the road, the new DPW design is exactly the same as the way it was before just adding a bike lane for the Santa Cruz bound but removing the safety buffer and adding road paint for cyclists Alameda bound.

    No real improvements here at all.

    Service vehicles for the homes on the east side will block the bike lane and cars and bikes will have to share the road in that scenario anyway.

    It actually brings us back to the third lane everyone was opposed to and seems completely unsafe for cyclists. Cars Santa Cruz bound will be sandwiched between two bike lanes. Last minute lane changes, which is very common in this area, will be completely dangerous for cyclists.

  2. For this portion of the road, I prefer the Community design.

    Cars traveling Santa Cruz bound will have the responsibility to check for cyclists going toward Santa Cruz or Alameda before they merge, slowing them down through this corridor.

    Alameda bound traffic is unaffected. And Cambo Bello maintains the turn lane. Win-win for all.

    This design is safer for cyclists by giving them a dedicated lane and buffer at the light, for pedestrians by shortening the crosswalk and providing a bulb-out so cars can’t use the parking spots as a lane to bypass traffic during peak hours, for motorists by maintaining clear lane destinations for Santa Cruz bound and Alameda bound travelers.

  3. The community design is a huge improvement over what the DPW design proposes. Removing the safety buffer from the residential driveways, as well as forcing cyclists to merge in an unsafe way is going to be dangerous. Please consider the community design as a way to get our area the kind of roads we need for the safety of cars, cyclists, residents and also pedestrians.

  4. These changes to the Y are just awful. The worst part is that cars that want to head left at the Y now have to be in the left lane. That means that cars in both lanes are shifting around, trying to be in the correct lane. Before, there was a lane that went in either direction at the Y, so if you were there it was fine. Now there’s a battle zone between Sand Hill and the Y where cars are shifting around so they’re in the right place at the Y.

    This creates a very dangerous situation for cyclists because drivers’ attention is spent on (1) making sure they’re in the correct lane and (2) watching out for other drivers that are moving around. Cyclists pressed up against parked cars are left to fend for themselves.

    These changes need to be undone.

  5. I prefer the community alternative rather than the current county design at the Y. The greater safety for pedestrians with the shorter, simpler crosswalk design makes sense to me. I live on Palo Alto Way. I strongly object to the left hand turn lane for southbound traffic on to Palo Alto Way. What is the necessity of the turn lane? It sure seems like the intention is to draw traffic away from the Sand Hill intersection by running cars through our neighborhood. Palo Alto Way is an alley for the first two blocks and then widens out a little in the last block where we live. At the end of our street people can make a right turn on Vine St. and proceed to the Oak Ave light at Sand Hill. It’s a shortcut that allows people to avoid the Santa Cruz Sand Hill intersection. There is a Las Lomitas Dist school bus stop at Palo Alto Way and Leland Ave, which is crowded with kids overflowing into the street waiting for the bus in the morning. Running commute traffic through this bus stop in our neighborhood is not safe for the kids!!!

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