The Metropolitan Transportation Commission (MTC) plans, finances, and coordinates streets and roads for the nine-county San Francisco Bay Area. Here's how the agency explains the existence of potholes and other deterioration to the nearly 8 million people who live and work in the area.

Pavement conditions around the region improved ever so slightly in 2015, but the typical Bay Area street remains seriously worn and likely to need rehabilitation soon. Data show the region's 43,000 lane-miles of local streets and roads registered an average pavement condition index (PCI) score of 67 out of maximum possible 100 points last year, an increase of a single point from the Bay Area's one-year PCI score of 66 in 2014. When calculated on a three-year moving average basis, however, the region's score remained unchanged at 66 for the seventh consecutive year.

"One of our goals is to get the network in every one of our cities and counties to a PCI score of 75 or better," says MTC Chair and Santa Clara County Supervisor Dave Cortese. "It's nice to see a small sign of progress, but we have a long way to go. And when you consider how old our pavement is, that gap is even bigger than it seems."

PCI scores of 90 or higher are considered "excellent." These are newly built or resurfaced streets that show little or no distress. Pavement with a PCI score in the 80 to 89 range is considered "very good," and shows only slight or moderate distress, requiring primarily preventive maintenance. The "good" category ranges from 70 to 79, while streets with PCI scores in the "fair" (60-69) range are becoming worn to the point where rehabilitation may be needed to prevent rapid deterioration. Because major repairs cost five to 10 times more than routine maintenance, these streets are at an especially critical stage. Roadways with PCI scores of 50 to 59 are deemed "at-risk," while those with PCI scores of 25 to 49 are considered "poor." These roads require major rehabilitation or reconstruction. Pavement with a PCI score below 25 is considered "failed." Among the region's three largest cities, San Jose (62) and San Francisco (67) both recorded three-year scores in the "fair" range, while Oakland (57) ranked in the "at-risk" category.

The Contra Costa County city of Brentwood and the Alameda County city of Dublin topped the list of Bay Area pavement rankings for the 2013-15 period, with both cities reporting average PCI scores of 85. Other cities with three-year PCI scores in the "very good" range include El Cerrito (84), Colma 83), Foster City (82), Clayton (81), Union City (81) and San Ramon (80). The lowest-ranked pavement in the Bay Area was found in the Marin County city of Larkspur, which recorded a PCI score of 39 for 2013-15.

In addition to Larkspur, other jurisdictions with three-year average PCI scores in the "poor" range include Petaluma (46), unincorporated Sonoma County (47), Orinda (49) and Vallejo (49).

Interestingly, MTC's Regional Streets and Roads Program later this year will recognize Vallejo for chalking up the biggest year-to-year PCI improvement of any Bay Area municipality. The Solano County city boosted the one-year PCI score on its 714 lane-miles of city streets by 10 points to 55 last year from 45 in 2014. Vallejo's three-year average PCI score of 49 reflects a two-point jump from the 47 registered for 2012-14. "Vallejo residents are starting to see the return on their investment," says MTC Commissioner and Solano County Supervisor Jim Spering, referring to the one-cent sales tax approved by city voters in 2011 to finance a wide range of municipal priorities, including public safety, pavement repair, streetlight replacement and economic development. "Sales tax dollars allowed Vallejo's public works department to completely repave more than 50 residential streets last year, with even more on the schedule for this year."

MTC also will recognize the Contra Costa County city of El Cerrito for having the best overall pavement management strategy of any jurisdiction in the Bay Area, and the San Mateo County city of Colma for the continuing high quality of its local street network.

The complete 2015 Bay Area Pavement Conditions Summary — including percentages of local roadways in "excellent" or "very good" and "poor" or "failed" condition, and a listing of average PCI scores for the arterials, collector roadways and residential streets — in all Bay Area counties and cities is available at

MTC's Vital Signs website provides even more detailed information on pavement conditions in each of the Bay Area's nine counties and 101 cities, including both block-by-block analysis and a record of every municipality's average PCI score for each year from 2003 through 2015. Those interested in a deeper look at the challenges facing the region's local street and road network are invited to visit the MTC website at and click on the link for a 2014 multimedia piece entitled "Street Fight: The Ongoing Battle for Better Bay Area Pavement."