Turning around the condition of a city's streets is difficult at best. After years of neglect, Los Angeles suburb Oxnard, Calif., is beginning the long, slow climb back to smoother rides for its 180,000 residents.
“We'd been operating on a worst-first repair basis and weren't keeping up with the pace of decline,” says Daniel Rydberg, capital projects manager for the Streets and Waterways Division of Oxnard's public works department. During the past six years, the division's largest budget was $10 million for fiscal year 2001–2002. By last year, cutbacks in federal and state funding had dropped the budget to $4 million.
“Both residents and elected officials seemed to have the perception that we weren't spending our funding effectively,” he says.
But that's changed. Late last year, the city council approved a $14 million bond issue and an overall $17 million divisional budget. Rydberg credits the loosened purse strings to a computerized pavement-wear model, known as a pavement management system, that proved to residents and officials the city's streets were deteriorating faster than the division could repair them.
Based on a road network's performance over a period of years, pavement management systems use mathematical models to predict how roads of certain types will respond to varying levels of improvement. Highway and street agencies use the models to determine the highest possible level of improvement a given amount of money will buy.
Oxnard's pavement management system is MicroPaver, developed in the late 1970s to help the U.S. Department of Defense maintain its vast inventory of roads. In 2000, Oxnard invested $100,000 to buy the software and hire a consultant, Pavement Engineering Inc. of San Luis Obispo, Calif., to assess 390 centerline miles of streets and 64 miles of alleys.
The software rates streets based on a pavement condition index (PCI) determined by the user after a thorough analysis of pavement conditions. Oxnard's streets, virtually all of which are asphalt, receive one of five ratings:
100–86; very good
- 85–71; good, needs sealant
- 70–56; fair, needs a light overlay or chip seal
- 55–31; poor, needs a heavy overlay
- 30–0; very poor, needs reconstruction.