Carousel Method

The purpose of this paper is to report the results of a study on the effectiveness of implementing the carousel method on a multilane freeway. When compared with other average vehicle occupancy (AVO) data collection methods, the functionality of the carousel method allows for the most accurate vehicle occupancy data to be collected on multilane freeways. With the power of a spreadsheet macro user-generated form, the carousel method has the capability to collect observation data, such as AVO data and vehicle type data, instantaneously. As data are collected, a power analysis can be executed to track the progress of the data collection process and can provide intermediate vehicle occupancy results. A 2014 Utah Department of Transportation study outlines how the carousel method was successfully implemented for multilane freeways. The results of the data analysis validated the carousel method as an acceptable method for collecting average vehicle occupancy data. The results of an AVO study in Utah are reported on the basis of the application of the carousel method. Results show that the AVO on express lanes is between 1.55 and 2.23 persons per vehicle and between 1.11 and 1.36 persons per vehicle for general purpose lanes. The details included in this report provide the basic building blocks of information that will allow municipalities and research teams to use the carousel method in multilane freeway studies.