Survey study of inventory data collection methods for public road systems

Regularly collecting inventory data for public roads of a state and reporting the data to the federal government facilitate the monitoring of performance and safety of highway systems for state highway agencies in the United States to possibly manage the highway infrastructures along a national guideline. It is required by the US Federal Highway Administration (FHWA) for every state Departments of Transportation (DOTs) to collect highway inventory data as part of their Highway Performance Monitoring System (HPMS). Traditionally, windshield surveys are the most popular inventory data collection method for state DOTs. However, the traditional method is inefficient, time-consuming, and unsustainable. As the advancements of computers, sophisticated sensors, and image processing, new technologies have been employed in the practice of inventory data collection. In addition, the methods used by state DOTs for collecting inventory data on local roads differ significantly from the methods for state maintained roads owing to the differences in ownership and resources. This paper presents the results of a survey study on the current practices of public road inventory data collection in the United States. In the study, relevant literature was reviewed and a comprehensive web based survey questionnaire was developed and distributed to state DOTs all across the US. The survey results showed that, a majority of state DOTs rely on local officials to acquire local road inventory data. Data submissions to a state DOT from the local agencies are frequently in accordance with state law or policies related to highway fund allocation. It has been a popular practice for state DOTs to use image and laser technologies based data collection vehicles to collect inventory data for state maintained roads at highway speeds. Many states also utilize more advanced methods to extract or integrate available data sources.