Proposal and Application of Parking Area Performance Measurement Methodology

The function of parking areas at expressway rest stops is to provide drivers with opportunities to park their vehicles for their own purposes, so the number of parking spots has been discussed. However, as the number of parking spots increases, the parking area becomes maze-like and the use of the parking spots becomes inefficient. This leads to skepticism that an increase in parking area capacity will contribute to enhancing parking area performance. Meanwhile, one vehicle is able to park in a parking spot when another vehicle exits the area that is fully occupied, so the condition of drop-by traffic at a rest stop can be discussed using the queuing theory by viewing a rest stop as a warehouse. Thus, this study aims to determine the applicability of the queuing theory when discussing drop-by traffic situations, while assuming a first-in first-out (FIFO) condition. For the applicability of the queuing theory of describing parking area performance, this study employed the ETC probe time-stamp data. The observed values from the ETC probe time-stamp data and FIFO assumed time lags are described, and the applicability of the observed ETC time-stamp data to representing the exact conditions was determined by comparing the number of vehicles parked on the hour every hour and those counted by the observed ETC probe time-stamp data. Finally, the applicability of the FIFO assumption was discussed using the correlation between the observed ETC probe time-stamp data and the FIFO assumed time lags calculated by the data. The results indicate that a FIFO assumption could alternate the observed the ETC probe time-stamp data. The number of vehicles staying on the hour every hour can be represented by the calculation results from FIFO assuming time lags. These findings show that it could be possible to determine the congregative situations of an expressway rest stop analyzed by the ingress and egress time-stamp records. Also, this result assumes any contribution to assessing the functional performance by measuring only the number of vehicles entering and exiting a parking area.