Alternatives for Estimating Seasonal Factors on Rural and Urban Roads in Florida, Phase II

Current practice at the Florida Department of Transportation (FDOT) employs seasonal factors (SFs) in the calculation of annual average daily traffic (AADT) at portable traffic monitoring sites (PTMSs). Permanent traffic monitoring sites (TTMSs) are first manually classified into different groups (known as seasonal categories). These groups are based on similarities in the traffic characteristics of roads and on engineering judgment. FDOT districts then assign a SF category to each PTMS according to the site’s functional classification and geographical location. It is assumed that seasonal variability and traffic characteristics at the short-term and permanent count sites are similar in the same geographic area. A previous study investigated traffic and land use data in Southeast and North Florida, with the goal of making the SF assignment process more objective and data-driven, as this would improve the accuracy in AADT estimation for PTMSs. The results from that study demonstrated the possibility of identifying the link between land use variables and SFs. In this follow-up study, a state-wide investigation is conducted, and multiple linear regression analyses are carried out. These are used to identify possible factors contributing to the seasonal fluctuations in traffic volumes for urban and rural locations with a TTMS in Florida. Based on these factors, a methodology is developed to determine which TTMSs are most likely to share similar SFs with a PTMS in urban areas. This methodology may be improved and expanded for application to rural areas.