Geographic information system (GIS) software is used almost daily by public agencies responsible for maintaining streets. Data might include segment identification number, construction date, maintenance history, subgrade type, and layer material, all of which can be stored in a geographic database, or “geodatabase.”
GIS has proven to be a versatile tool for integrating the information technology and data investments within organizations. Combing these historic data with current information on pavement conditions provides a data foundation for integrating a pavement management system (PMS) application into a GIS.
When this combined information is made available to a PMS through a geodatabase, you can systematically evaluate an entire road network and develop work plans for maintaining its pavement to a predetermined standard with available resources.
Pavement Data Collection
APMS is only as accurate as the pavement condition data supporting it. Data collection is the most important factor in establishing a successful maintenance program. To keep data current, your department should collect data that covers the entire road network every two to three years. It also establishes a basis of comparison by which to measure deterioration over time.
Using an imaging van to regularly cover the network is the most efficient way to ensure current data. An array of digital cameras captures images of pavement distress, georeferenced with onboard global positioning system receivers. A laser profiler adds information on surface characteristics. Data from any stretch of this linear referenced library can be called up on demand from within a GIS.
Commercially available applications for pavement management, such as the U.S. Army Corps of Engineers-developed Micro PAVER (http://owww.cecer.army.mil/paver/Paver.htm), use GIS-stored data to evaluate pavement condition for distress, roughness, and rutting. Distress factors are automatically identified—such as transverse, longitudinal, alligator, or block cracking—and are rated for severity. The cumulative ranking of distress in all street segments is used to create a pavement condition index for use in prioritizing maintenance efforts.
The end product of the PMS is a multi-year plan for rehabilitating with consideration for severity of distress, the importance of the artery, and the budgetary constraints of the department. Predictive analysis offers choices for the best course of action for treatment within several user-defined parameters. The materials and costs related to specific treatments are estimated in a maintenance, rehabilitation, and reconstruction list.
The Benefits Of GIS
Integrating a PMS with a GIS offers distinct advantages over employing a PMS alone. The ability to share information with other departments such as sanitation, traffic, and public safety, who have an interest in the same data, is a tremendous benefit. The map interface provides an overview of the entire network. Updates made to data fields are displayed on the map automatically. Attributes can be color-coded according to user preferences.
The linear referencing capability of GIS allows data, including pavement views, to be accessed for any point along the network. A geodatabase also stores related information on street assets (right of way, maintenance history, traffic counts), which is essential for creating a complete model.
GIS is excellent for integrating other type of software applications. It serves as a bridge to bring work orders into the PMS. Asset data can be exported from the GIS into a financial management application to comply with GASB 34 reporting.
— Jeffrey Allen is a public works specialist at ESRI Inc., Redlands, Calif.