Assessment of Data-Collection Techniques for Highway Agencies

In the last decade, many agencies within Canada and the United States have initiated programs to assess the effectiveness of their traffic-monitoring programs and the value gained from their traffic-monitoring dollars. A project was initiated by the British Columbia Ministry of Transportation to assess the accuracy of the existing traffic-monitoring system and to compare it to alternatives for estimating traffic volumes on the highway network. The study included a review of findings from similar projects by the New Brunswick Department of Transportation and the Prince Edward Island Department of Transportation and Public Works. The options for traffic data collection considered by all three provincial agencies and the accuracy and cost implications that can be expected from each option are presented. Two methods for expanding short-term traffic counts to estimate average daily traffic volumes are discussed. The reported accuracy estimates allow practitioners to better understand cost and accuracy trade-offs.