County Road Improvements

Working towards a safer and smoother drive for Marin's residents and visitors.

The Marin County Department of Public Works (DPW) 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.

Road-paving project on Lucas Valley Road

Annual Road Improvement Budget by Sources

DPW plans, designs and implements multiple paving and road improvement projects each year, covered by the Road & Bridge Rehabilitation Fund.
Staff work hard to secure additional state and federal funding sources in an effort to increase DPW’s workload capacity. Those funding boosts, such as CA Senate Bill 1 (SB1), make it possible to address priority projects earlier than previously possible, thereby saving money in the long term by avoiding further roadway deterioration that would necessitate more expensive repair projects. 
Road improvement work on Point San Pedro Road

Road improvement work in West Marin

Pavement Condition Index: Assessing Road Quality

Pavement Condition Index (PCI), which is measured by specialized independent contractors, is a numerical grade between 0 and 100.  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.” It is used to indicate the general condition of roadway pavement and categorizes the overall quality of a road network for a given jurisdiction.
For DPW, our PCI score gives a solid snapshot of our overall progress on improving the County’s roadways. The numerical grade helps staff track the service life of the road network and prioritize roads that need to be addressed. Similarly, PCI plays a key part in identifying roads which could benefit from pavement maintenance treatments, like surface sealants, which help extend service life of a road and avoid the need of more extensive rehabilitation projects.
The PCI assessment is required by the Metropolitan Transportation Commission (MTC) in order for DPW to be eligible for grant funding. To complete the circle, grant funds then go back towards continuing to improve the County's road network. 
When Marin's road network first started receiving PCI scores in 2003, the roadways in unincorporated Marin County scored a 55 out of 100, ranking them in “At Risk” condition. Since then, DPW has made progress by prioritizing maintenance and repaving projects with all available funding.
Completed road improvements in West Marin
PCI Score: 0-25 “Failed,” 25-50 “Poor,” 50-70 “At Risk,” 70-100 “Good.” 

Paving work being conducted at night.

Marin County's paving program approach and long term goal

In terms of making road improvements, projects become exponentially more intensive and expensive as the condition of the road deteriorates. A good road generally only requires preventative maintenance projects to keep it in good standing, whereas a failed road needs full-depth reconstruction that is a costly and time consuming. For example, $1 million could fund maintenance for 15 miles of good roadway versus only 1 mile of failed roadway being rehabilitated.
The Marin County paving program, revised in August 2022, utilizes various strategies to improve road conditions, including PCI scores, to keep roads that are in the "Good" PCI category in that condition. Funding is allocated accordingly to first maintain the roads in the good condition category and then addresses targeted roads in the other three categories, with the goal of ultimately bringing those roads up into the good condition category.
As the road network quality improves over time, the budgetary split between funds towards maintenance projects versus full rehabilitation projects would be adjusted to account for the overall improved conditions. More money would shift to maintaining the growing category of good roads, while still balancing the more demanding projects of the other categories.
The ultimate goal is to have the full County-maintained roads network reach "Good" status. By potentially reaching a full network of good roads, the total maintenance cost of the infrastructure could be approximately $4 million (not adjusting for inflation at that point in time), thereby reducing the budgetary need of the paving program and allowing the remaining funds to be utilized elsewhere. 
Sir Francis Drake Boulevard after Upgrade The Drake improvement project

Map of County-maintained roads with corresponding PCI score

Important notes:  1) PCI scores shown on this map are from data provided by the Metropolitan Transportation Commission. 2) The address search bar will only produce results for unincorporated areas of Marin County, not from the incorporated town/city jurisdictions.