TO: Board of Supervisors
FROM: Steven Lederer, Director of Public Works
REPORT BY: Sydney Barclay, Associate Engineer
SUBJECT: Presentation regarding Edge line Rumble Strips and Amendment 2 to Agreement No. 250052B with Sanderson Bellecci, Inc. for the HSIP Cycle 11 "Silverado Trail Intersection Improvements" project, RDS 22-26.
RECOMMENDATION
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Receive a presentation on edge line rumble strips on Napa County roadways and provide direction; and approve Amendment No. 2 to Agreement No. 250052B with Sanderson Bellecci, Inc. for additional engineering design and support services for the "HSIP Cycle 11 Silverado Trail Intersection Improvements" project RDS 22-26. (Fiscal Impact: $267,532 Expense; SB-1 Fund; Budgeted; Discretionary)
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BACKGROUND
The Department of Public Works will provide a presentation to the Napa County Board of Supervisors regarding the advantages and disadvantages of using edge line rumble strips on County-maintained roadways, with a particular focus on their potential implementation along Silverado Trail. As directed by the Board, the "Bale, Big Ranch, Lodi, Silverado Trail, and West Zinfandel Paving, RDS 25-06" project, completed in the fall of 2025, included the installation of rumble strips as a pilot effort. The pilot installation has generated a range of feedback from nearby residents, businesses, and roadway users.
Public Works reviewed countywide collision data from fiscal year 2024-2025 and identified a total of 273 reported accidents in Napa County. Of these, 160 were single-vehicle collisions, with the majority classified as lane departure events. While some incidents involved external factors, such as animals crossing the roadway, the vast majority of accidents were attributed to driver inattention, distraction (commonly phone use), fatigue, or impairment (DUI, etc.). Of the 24 confirmed incidents in which drivers fell asleep, 11 occurred between 1:00 PM and 5:00 PM.
On Silverado Trail, the collision rate is approximat...
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