Examining the Effects of King County Metro Carpool Incentive Fund

Abstract

How should public transit agencies deliver mobility services in the era of shared mobility? Previous literature has recommended that transit agencies actively build partnerships with mobility service companies from the private sector, yet public transit agencies are still in search of a solid empirical basis to help envision the consequences of doing so. This study presents an effort to fill this gap by studying a recent experiment of shared mobility public-private partnership. The carpool incentive fund program launched by King County Metro in the Seattle region. This program offered monetary incentives for participants who commuted using a dynamic app-based carpooling service. Through descriptive analysis and a series of logistic regression models, we found that the monetary incentive to encourage the use of app-based carpooling generated some promising outcomes while having distinct limitations. In particular, it facilitated the growth of carpooling by making carpooling a competitive commuting option for long-distance commuters. Moreover, our evidence suggested that the newly generated carpooling trips mostly substituted for single-occupancy vehicles, thus contributing to a reduction of regional VMT. The empirical results of this research not only will help King County Metro devise its future policies but also highlight an appealing alternative for other transit agencies in designing an integrated urban transportation system in the era of shared mobility.