Planning a Real-time Ridesharing Network: Critical Mass and Role of Transfers

For decades now, ridesharing has been identified as a promising solution to cope with traffic congestion and pollution. Real-time ride-sharing in particular, seems to have great potential to boost ridership. But despite several policy attempts, it hasn’t picked up significantly in metropolitan areas. This paper aims at understanding why, by quantifying the critical mass or “tipping-point” in the number of drivers offering seats for a casual or dynamic ridesharing line to work. It shows that ridesharing transfers can be used to reach this critical mass. Based on a simple road network and real origin-destinations in the Lyon metropolitan area, the performance of such a ridesharing network is compared to public transport or ride-alone solutions based on a probabilistic approach through Monte Carlo simulations. Policy recommendations are given, of which designing a network of ridesharing “lines” and “hubs”. Proof of reliability improvement and first hints on public authority’s involvement are given.