Arroyo de la Laguna Creek Bridge Project Subject Webpage

This Subject Web Page was updated on September 27, 2018.

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Sunol Citizen’s Advisory Council Unanimously Supports the Following Letter to CalTrans

SCAC Council member Connie DeGrange offered the following letter at the 9/19/18 SCAC council meeting and her motion to adopt the letter as written was unanimously approved as the Council’s recommendation. Tom Harland’s drawings of a proposal for the historical restoration of Sunol’s Four Corners intersection was enthusiastically included by the members of the council:

SCAC comments scoping Arroyo Laguna Bridge 9-24-18

Inform Sunol Traffic Study Group Submits Recommendation to SCAC Regarding Bridge Project

Representing the Inform Sunol Traffic Study Group at the 9/19/18 Sunol Citizen’s Advisory Committee meeting, Dan Reasor presented a recommendation that is captured on the SCAC Audiotape beginning at 1:26 on the tape:

Click Here to Listen to the SCAC 9/19/18 Audio Minutes of the Meeting

Prior to the 9/19 meeting, representing the Inform Sunol Traffic Study Group, Jim O’laughlin submitted the following letter to the SCAC summarizing the study group’s recommendation:

Recommendations of the Inform Sunol Traffic Study Group regarding the Caltrans proposal for the Arroyo de la Laguna Bridge Project

Letters and Comments Received from Subscribers



Roundabout near Truckee Nevada in pdf

Env_PerferredAlternative1_November2015 in pdf

On August 3, 2018, Cal Trans Held an Initial Scoping Meeting at Sunol Glen School

CalTrans follows Up Unsatisfactory Notice with an Informative Scoping Meeting

  • Three Alternatives Reviewed for Bridge Repair
  • A Roundabout is back in consideration for Niles Canyon Traffic Mitigation
Sunol Citizens were none too happy about receiving email notice one day before the Thursday, August 2nd, 2018 CalTrans Initial Scoping meeting. The project will address significant issues with the Arroyo De La Laguna Creek bridge. The bridge which is a short walk to the East from Main Street on Niles Canyon Road and is the passage to and from the Four Corners eastern entrance of Niles Canyon near the gate to the Willis Polk Water Temple. Fortunately, the dozen or so Sunolians in attendance were treated to an informative presentation led by Project Manager Jack Siauw with his supporting staff from Caltrans.


Five years ago, an inspection revealed “scouring” due to the erosive force of moving water around the piers that hold up the bridge. A 2014 estimate of $7M for repairs has since grown as CalTrans must include seismic upgrades and ADA compliant sidewalks to the scope of the work. Of three alternatives offered Thursday night, one is a bridge retrofit while two involve bridge replacement. All other options would allow thru-traffic to flow during the work.
Following sincere apologies for the notification system with promises to address its deficiencies, Jack Siauw said that this Project is in ‘early planning phase.’
CalTrans’ Niles Canyon web page is

Project Manager Jack Siauw offered his own business phone contact number: (510) 622-8824.

On Tuesday, August 8th, Jack Siauw reached out to Inform Sunol and advised, “We wanted to let you know that the comment period for the scoping meeting for the Arroyo de la Laguna project has been extended by 30 days. Comments will now be accepted until October 2, 2018.”
Caltrans will accept comments until October 2, 2018 via postal mail at:
California Department of Transportation
District 4
Office of Environmental Analysis
Attn. Brian Gassner
P.O. Box 23660, MS 8B
Oakland, CA, 94623-0660
Or, comments can be provided via email to
The extension will allow more time to review alternatives and for Sunolians to contribute their comments.
Some Sunolians present at the meeting requested bicycle access, in any event, noting that none was planned for any of the three options. The CalTrans staff promised that no ‘school property’ would be impacted by any of the scenarios. As is, the bridge is 39’ wide, 310’ long, features 2 lanes with 4.5’ wide sidewalks and is held up by two piers in the active creek channels flowing underneath.
Alternative #1 would repair the foundation scouring and remove and replaced railings with two options presented: one made of steel and the one made of concrete. The old style arches under the bridge must be replaced. The sidewalk area would be removed then improved to ADA standards, and an improved edge median would be installed. Seismic retrofit and upgrades will require providing a wider bridge deck. The current footprint of the bridge would not change. In total, Alternative #1 has an estimated cost of 10 million dollars.
Alternate #2 would replace the entire bridge structure and offer two travel lanes like the current bridge. Better railings, wider sidewalks, and wider edge lanes would be included in the new 46 feet wide structure with almost double the width of stream flow area and use no piers in the main flow channel. Alternative #2 currently does not provide for bicycle traffic and has an estimated cost of 11 million dollars.
Alternate #3 replaces the entire structure with a 56-foot-wide bridge with three 12 foot travel lanes, two-foot wide shoulder lanes, and sidewalks on both sides measuring six feet wide. The additional middle eastbound lane land would address the issue of Main street access to 84/Paloma Road. The underside would allow for a greater storm flow volume having no main channel piers. The estimated lifespan of the bridge is 100 years. Currently offering no bike lanes, Alternative 3 has a current price tag of 13 million dollars.
In all three scenarios, work Construction will allow 2-way traffic on the bridge. They will construct a parallel half bridge then move traffic over.
In addition to the recommendation to add a bike lane, residents asked if there has been a traffic study to see how much traffic actually turns left onto Pleasanton-Sunol from Niles Canyon Road (which would quantify the benefit of the additional lane offered in Alternate #3).
A Sunolian asked if there had been a study to see where the water goes after it flows under the bridge, while another resident asked how the scenarios would help reduce the pass-through commute traffic that currently flows daily through Main Street.
As for a schedule, the EIR development could begin later this year, with a Draft EIR due Spring 2019, and the Final EIR due Spring 2020. Construction would take place during 2023-24. CalTrans assured that two-way traffic would always be in place during construction and that that there is a lot of room for refinements, and suggestions are welcome.
Several audience members requested that serious consideration is given to replacing the ‘troublesome signal lights’ planned at Pleasanton/Sunol Rd with a well-designed traffic circle or “Roundabout.”
A CalTrans’ webpage declares that traffic flows faster with fewer accidents compared to signal light systems. One reason that signal light systems are inferior is due to the ‘pulsing effect ’that leads to rear-end strike accidents. Please check out this single page: CalTrans_Honors_Roundabout_Project
Special Thanks to Inform Sunol subscribers Dan Reasor and Rosemary Chang for taking notes at the meeting and providing the pictures used in preparing this story.