Title
Review and Discuss Proposed Quick-Build Improvements to the Lincoln/Walnut Intersection (Discussion)
Body
To: Honorable Chair and Members of the Transportation Commission
From: Lisa Foster, Secretary to the Transportation Commission
Allen Tai, Planning, Building, and Transportation Director
EXECUTIVE SUMMARY
Staff will present proposed quick-build improvements to the Lincoln/Walnut Intersection which will prohibit through and left turn vehicular movements from Walnut Street, forcing right turns at Lincoln Avenue. The goal of the improvements will be to reduce the high number of broadside collisions that have occurred at this intersection, which is identified as a high collision intersection in the Vision Zero Action Plan.
Staff seeks Transportation Commission feedback and public comment on the proposed improvements and associated traffic restrictions.
BACKGROUND
Lincoln Avenue is a primary east-west arterial within Alameda with convenient access from the main island to the Park Street bridge and the Miller-Sweeney bridge on Tilden Way. Most of the primary intersections on Lincoln Avenue are controlled with traffic signals including the adjacent intersections of Lincoln/Willow, Lincoln/Oak, Lincoln/Park, and several others along the corridor.
The intersection at Walnut Street is the first non-signalized intersection for vehicles entering the corridor from either the Park Street bridge or from Tilden Way. Right-of-way control is through a two-way stop sign with traffic stopped on Walnut Street.
As part of the Vision Zero Implementation Plan, the Lincoln/Walnut intersection was identified in 2020 as high collision intersection with transformative potential. Many of the collisions reviewed in 2020 were vehicle-to-vehicle broadside collisions occurring as people driving on Walnut attempted to turn left onto or to cross Lincoln.
Prior to 2020, Lincoln Avenue was a four-lane road through the Walnut intersection, reducing to a three-lane road (two through lanes and a two-way left turn pocket) as it approached Oak Street. The 2020 improvements extended the three-lane road configuration west and through the Walnut Street intersection. The two eastbound lanes were merged into a single lane approximately 350 feet west of Walnut Street and the single westbound lane extended through the intersection. Dedicated left turn lanes were provided on Lincoln at the intersection. The intention was to simplify the intersection with fewer through lanes on Lincoln Avenue, improve sight distance for vehicles on Walnut Street, and shorten the effective crossing distance for pedestrians.
All-way stop sign control was evaluated for this intersection in 2020, and based on vehicle counts from late 2019, the intersection did not meet the warrants for a stop sign. The traffic volumes on Walnut Street were not large enough to justify added stop signs. Additionally, the intersection did not meet the warrant for collision experience which is five or more per year. A secondary consideration in the all-way stop evaluation is that the entire Lincoln Avenue corridor is traffic signal controlled and placement of a stop sign at a low volume intersection would likely lead to low compliance from drivers on Lincoln Avenue.
In early 2025, in response to continuing collisions at the intersection including the 2021 pedestrian fatality, the City completed a second round of improvements at the Lincoln/Walnut intersection. Flashing beacons were installed at both crosswalks to alert motorists of pedestrians crossing the intersection. The eastbound lane merge was moved further west, closer to Willow Street, bulb-outs were expanded and painted for increased visibility, and vertical elements (plastic bollards) were added.
Neighbors at the intersection reported multiple vehicle-to-vehicle broadside collisions following the 2025 improvements, providing video evidence from doorbell cameras.
DISCUSSION
High Number of Broadside Collisions
Collision data from 2020 has been augmented by an Alameda Police Department dataset of reported collisions from 2009 through October 2024 and staff has completed a preliminary review of the data. There were a total of 38 reported collisions at the Lincoln/Walnut intersection during the nearly 15-year reporting period, second highest of any intersection within Alameda, and highest of any non-signalized intersection. Nearly 80% of the collisions were reported as broadsides, a collision consistent with vehicles trying to enter an intersection.
The dataset can be further separated into collisions occurring prior to 2020 and those occurring after 2020, comparing the collision rate. While a 7% reduction was observed after 2020, this reduction is similar to the citywide reduction of 9% in collisions after 2020, and far less than the nearly 40% reduction in collisions observed at intersections where safety measures have been implemented. It is acknowledged that traffic data from this time period was affected by changed traffic patterns resulting from the COVID-19 pandemic. Nonetheless, the traffic data can be used comparatively and provide insights to identify problematic intersections and judge the effectiveness of traffic safety measures.
Anecdotally from neighbor accounts, traffic on Walnut Street has increased since Park Street was reduced from four lanes to two in 2020, with drivers seeking to avoid congestion on both Park Street and Oak Street. These observations, however, were not confirmed with traffic counts collected in late 2025. A comparison between traffic counts collected in 2019 and 2025 show roughly the same order of magnitude with approximately 120 vehicles and pedestrians approaching the intersection from Walnut Street during the AM peak, increasing slightly to approximately 130 vehicles and pedestrians during the PM peak. It is worth noting that the collision rate on the Park Street corridor from San Jose to Lincoln has reduced by 33% after 2020, or in other words, a reduction of 43 collisions since 2020.
Not surprisingly, traffic counts collected in late 2025 still do meet warrant criteria for an all-way stop. The fact that the Lincoln/Walnut intersection continues to see a high number of collisions has prompted staff to evaluate other alternatives to improve safety at the intersection.
Diverter Island to Limit Broadside Collisions
Staff has identified a diverter island which would restrict through and left turn movements from Walnut Street as the preferred method which is being presented to the Transportation Commission for feedback. An example of the diverter island is included as Exhibit 1. The proposed diverter island would restrict vehicular movements only, pedestrians and bicycles could continue north or south across Lincoln Avenue in much the same manner as they currently do. It would be recommended that bicycles use the crosswalk and flashing beacons to cross Lincoln.
Although traffic data do not show a substantial volume increase from 2019 through 2025 is still likely that drivers are bypassing Park Street or Oak Street and using Walnut Street to access the Park Street bridge. Requiring all Walnut Street traffic to turn right at the intersection would dramatically reduce the potential collision exposure at the intersection and may encourage drivers to remain on Park or Oak Streets when heading to or from the bridge. Additionally, northbound drivers diverted onto Lincoln would have the opportunity to continue north with a left turn at Oak Street, a signalized intersection. Similarly, southbound traffic diverted onto Lincoln would have the opportunity to continue south with a left turn at Willow Street, also a signalized intersection.
Alameda Fire Department has been consulted and does not have objections to the through and left turn restrictions. Due to its narrow width, Walnut Street is not a primary response route and is typically only accessed by fire trucks for calls on Walnut Street. Additionally, the diverter island would be constructed to allow larger fire truck vehicles to continue through the intersection if needed.
On November 17, 2025, City staff met with the Mayor and interested immediate neighbors at the intersection to observe the afternoon traffic conditions and hear their observations and concerns about the intersection. While traffic speed on Lincoln was a contributing concern, the primary issue was repeated collisions at the intersection and fear of personal injury and recurring property damage. Stop signs and traffic signals were discussed, and staff presented the diverter island concept restricting through and left turn movements as a quick-build option of a possible phased approach.
A quick-build diverter island can be installed in summer 2026 and observed for several months to a year. Traffic data was collected in December 2025 at three intersections: Lincoln/Willow, Lincoln/Walnut, and Lincoln/Oak to serve as a baseline for traffic movements. Staff would collect traffic data at these same three intersections three to six months after the diverter island was installed to understand how drivers have modified their behavior and evaluate any potential adverse impacts.
Lincoln/Marshall/Pacific Project
Separately, the Lincoln/Marshall/Pacific Safety Improvement Project is in design and still on target to begin construction in 2027. If successful, the quick-build diverter island could be made permanent with the larger corridor project. If deemed unsuccessful, staff would continue to evaluate options and pending further warrant analyses, may recommend a full traffic signal be installed at the intersection. It is worth noting that traffic signals are expensive, $800,000 to $1M, would create additional delay for the primary movement on Lincoln Avenue, and are not always a panacea to reduce collisions.
Outreach
In addition to the recent on-site meeting with neighbors and ongoing engagement with them, notices have been mailed to all residents within 300 feet of the intersection alerting them of the January 28, 2026 Transportation Commission and providing opportunities to provide comment.
ALTERNATIVES
• Construct a quick build diverter island to prevent through and left turn movements from Walnut Street to Lincoln Avenue with the option to make permanent as part of the larger corridor project
• Upon assessment of warrants for potential traffic signal installation, pursue the potential grant funding for a new signal installation. This alternative may take 2 or more years to acquire funding, complete design and construct the improvements.
• Do nothing
• Transportation Commission may provide alternative direction to staff for consideration
FINANCIAL IMPACT
A quick-build design for a diverter island could be incorporated into the existing design budget for the Lincoln-Marshall-Pacific corridor project. Funding for the quick-build construction is available with Capital Project C61000, Street Safety.
MUNICIPAL CODE/POLICY DOCUMENT CROSS REFERENCE
The Vision Zero Policy directs staff to consider safety as the highest priority when balancing competing needs and demands for space within the public right-of-way. The high number of collisions occurring at the Lincoln/Walnut intersection highlights the need for quick action.
General Plan Mobility Element, Goal 2, Safety, is to “Eliminate fatalities and severe injuries on Alameda’s streets, avenues, sidewalks, crosswalks, paths and trails by 2035.” Reducing potential collisions at this intersection supports this goal. Several other General Plan Policies and Actions identify safety for all modes of transit as highest priority.
General Plan Mobility Element Policy MU-13, Alameda Street Grid, calls to “Manage and extend the Alameda street grid to maintain the character of Alameda, reduce traffic, and maximize mobility, access, and safety for all modes of transportation.” While the proposed diverter island would restrict vehicular access across Lincoln and redirect vehicular traffic to the adjacent streets for continuation, pedestrian and bicycle traffic would still be able to cross Lincoln.
RECOMMENDATION
Receive the presentation on the proposed quick-build improvements to the Lincoln/Walnut Intersection, provide feedback on proposed changes, and recommend alternatives as appropriate.
Respectfully submitted,
Erin Smith, Public Works Director
By,
Scott Wikstrom, City Engineer
Exhibits:
1. Example Diverter Island