This project focused on the collection of new data to add to the NCDOT School Traffic Calculator (STC), with a specific focus on estimates generated for vehicular rates and queue length. School travel data was collected at schools across North Carolina. This sample included schools of various types in varied geographic areas. Schools continue to be constructed at a rapid pace across North Carolina as the state experiences population growth, particularly in urban regions. Furthermore, existing schools throughout North Carolina and the U.S. continue to experience increases in child passenger pick-up and drop-off, regardless of school age or location (NHTSA, 2009). As a result, accurate estimation of school site queue length needs and trip generation rates are critical to maintaining and improving the transportation safety of North Carolina's communities.
This work is significant for NCDOT due to the potential for enhanced accuracy of school travel mode and queue length estimation. Increased accuracy in queue length needs will lead to school site design and traffic management plans that better accommodate school travel demand and corresponding needs. Effectively accommodating passenger vehicle queues will promote improved traffic safety and operations in communities throughout North Carolina with new school construction and existing schools that have difficulties with queue spillover into surrounding roadways.
The most robust estimates and updates to the calculator recommended based on this research study are drawn from the public elementary school sample (n = 13, while all other samples had seven or less observations). For this category, the existing STC high demand length estimate is comparable to the high demand length projected from the field data. To ensure a conservative estimate of queue lengths, a 95th percentile estimator was implemented in the calculator recommendations.