Fairfax-Bolinas Road CONDITION UPDATES, thank you for your patience: At milepost 5.73, Fairfax-Bolinas Road will be open on weekdays and weekends from 12/16/24 through 1/1/25 (weather permitting), with traffic controlled through a single lane with alternating access. This is to accommodate the holiday traffic. From 1/2/25 through 1/5/25, the road will be closed at milepost 5.73 to allow for construction activities as the project nears completion, weather permitting. After 1/5/25, it is anticipated that the road will be closed from Azalea Hill to Ridgecrest on weekdays only. By mid-January, the project is expected to be completed and the roadway will fully reopen. See project webpage for details.

Paving Program

About

Paved roadThe program maintains over 420 miles of roadway across unincorporated Marin County, and the condition of that road network is crucial to the daily lives of the diverse communities of Marin. Keeping the roads network operational is a major responsibility and massive undertaking for Public Works, requiring year-round strategic planning. In addition to focusing on maintaining this infrastructure, the specific goal of improving overall roadway condition has been one of the main priorities for the Marin County Board of Supervisors since they initiated the Road & Bridge Rehabilitation Fund in 2014 to support this program.

Contact us - our staff is always available to answer questions and offer assistance as needed.

Assessing road quality

The "Pavement Condition Index" (PCI) is a numerical grade between 0 and 100 that is used to indicate the general condition of road pavement. A ranking of zero to 25 is “Failed,” 25 to 50 is “Poor,” 50 to 70 is “At Risk,” and 70 to 100 is “Good.” A score of 100 would be a newly paved road.

Originally developed by the United States Army Corps of Engineers as an airfield pavement rating system, it was later adapted for roads and has become the national standard. The scoring is determined by independent engineering consultants using standardized methods of visual surveying. Many factors affect PCI including pavement age, climate and precipitation, and traffic loads. The numerical grade helps Public Works staff track the service life of the road network.  Similarly, PCI helps staff identify roads which could benefit from cost-effective pavement maintenance treatments, such as surface sealants, which help extend service life of a road and avoid the need of more extensive rehabilitation projects.

In terms of making road improvements, projects become exponentially more intensive and expensive as the condition of the road deteriorates. A "good" condition road generally only requires preventative maintenance to keep it in good standing, whereas a "failed" condition road needs full-depth reconstruction that is a costly and time consuming. For example, $1 million could fund maintenance for 14 miles of good roadway versus only 1 mile of failed roadway being rehabilitated.

Public Works staff strategically select treatments or paving methods and implement them at the right time to maximize a specific road segment's PCI and extend the service life of existing pavement. This allows the County of Marin to improve more miles of roadway each year in the most efficient and cost effective manner possible. The ultimate goal is to have the full County-maintained roads network reach "Good" status.

5-Year Pavement Resurfacing Projects Plan

In the ongoing mission to improve roads across unincorporated Marin, Marin County Public Works has developed a five-year pavement resurfacing projects plan. The current schedule shown on the online interactive map indicates approximately 199 miles of roadway to be improved between the 2025 and 2029 paving seasons. The estimated cost for those improvements is $87 million.  

Clicking on road segments on the online interactive map shows information about the possible approach that could be used to improve the roadway. “Pavement Maintenance Treatment” and “Pavement Preservation Treatment” approaches generally consist of removing and replacing isolated sections of failed asphalt, then adding a treatment to seal, smooth and extend the useful life of the pavement.   

Road segments expected to receive “Pavement Rehabilitation” and “Pavement Reconstruction” approaches typically entail having the existing asphalt surface ground down and a new layer of asphalt applied, or they may receive an overlay of new asphalt directly over the existing surface. 

It should be noted that the vast majority of the projects are still in the planning phase. Until a project enters the design phase, the specific treatment that will be used within that designated approach is not known. For projects that have entered the design phase and have specific details, please visit our webpage of active projects.  

Breakdown of treatments within the Plan's 4 approaches

There are a variety of treatment methods that are typically included in each approach, some of which overlap:

  • Pavement preservation
    • Minor digouts
    • Crack sealing
    • Slurry seals
  • Preventative maintenance
    • More extensive digouts
    • Slurry seals
    • Microsurfacing
    • Chip seals
    • Rubberized cape seals
  • Pavement rehabilitation
    • Rubberized cape seals with leveling
    • Asphalt concrete overlays and inlays
  • Pavement reconstruction
    • Removal and replacement of the asphalt concrete surface
    • Cold-in-place asphalt recycling
    • Full depth reclamation
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