TRB Paper 01-3440 Estimation of Annual Average Daily Traffic in a Florida County Using GIS and Regression

Accurate Annual Average Daily Traffic (AADT) information is important to many applications including roadway design, air quality compliance, travel model validation, etc. Yet complete or even extensive coverage of a network to collect traffic count data is impractical due to the cost involved. There have been studies to estimate AADT for interstate highways, expressways, urban roads, and rural roads. Such efforts are often hampered by the lack of relevant detailed information that adequately explains variations in the traffic counts. In this paper, a multiple linear regression model of AADT on local roadways in a large urban area is presented. By employing geographic information system (GIS) technology, a variety of land use and accessibility measurements are developed and tested. While most are statistically significant, few add enough explanatory power to be practical and useful. Four models are presented, which achieved R of 0.66 to 0.82. The predictive power of the models are also examined.