Just as there are a variety of funding sources for pavement maintenance, and different ranges of pavement quality, so too are there various classifications for local streets and roads. A roadway’s “functional classification” is determined primarily by the number of vehicles that use it. About 70 percent of roadways are residential (see chart at right). These are the streets and roads that run through neighborhoods and carry few buses or trucks, other than waste management vehicles. Collector roadways serve to “collect” traffic from the residential streets and deposit them onto arterials, which carry the most car, truck and bus traffic, and which typically provide an outlet onto state highways or freeways. Federal funding can be used only on roadways that have a functional classification of collector or arterial, or roughly 28 percent of the Bay Area street system.
Local streets and roads, which are owned and maintained by cities or counties, account for 90 percent of the Bay Area’s total lane mileage. State highways (including interstate highways) are maintained by Caltrans and comprise about 7 percent of total mileage. Roadways that fall under the responsibility of the federal government primarily include those in national parks, reserves, tribal lands and military installations. About 2 percent of roadways are either privately owned, or are owned and maintained by special districts such as the East Bay Regional Park District, the California Department of Parks and Recreation or the Golden Gate Bridge, Highway and Transportation District.
Many factors affect a city’s or county’s pavement condition index, or PCI score. These include pavement age, climate and precipitation, traffic loads and available maintenance funding. A municipality with new housing developments and new streets may have a high overall PCI, while an older, urbanized jurisdiction may have a much lower PCI, even though both are practicing pavement preservation. Cities and counties that practice preventive maintenance will have lower long-term pavement costs and will safeguard their investment in local streets and roads.
Continue reading: part 4, Importance of Early Intervention.