Abstract
This paper discusses an in-depth evaluation study of the Washington State Department of Transportation highway data development and analysis activities. The paper describes statistically-based procedures and recommendations that were developed to streamline the highway data collection program. Opportunities to reduce manpower and equipment costs, streamline work activities, improve the quality of data collected and provide accurate and timely data for the various users were identified. Given the focus on highway data, a major effort was devoted to the Department’s traffic counting program. However, many data items and programs were considered, with the following receiving particular attention: traffic volume counting, including estimation of annual average daily traffic at any location throughout the state highway system; associated seasonal, axle and growth factors; vehicle classification; truck weight; and the relationships between the statistical sampling requirements recommended for these items and those associated with the FHWA Highway Performance Monitoring System (HPMS) in the state. By employing statistical sampling methods that complement the HPMS sample, a strong potential exists to significantly improve the cost-effectiveness of a statewide highway data collection program.