A simulation of a Mobility on Demand (MOD) based ride sharing system finds limited gains in terms of vehicle miles traveled and vehicles on the road.
MOD schemes are an emerging transportation concept facilitated by information technology (IT) and ubiquitous internet and smartphone access. The idea of MOD is that mobility services are made available to travelers on an as needed basis and in theory travelers can seamlessly move about without needing private vehicles. Shared autonomous vehicles (SAVs) may be a key component of this system.
Despite their promise, few studies have attempted to understand whether SAVs will actually result in improved mobility for end users and reduced traffic congestion.
This study helps answer that question by simulating different ride-sharing operational schemes. The researchers used "taxi trace" records in San Francisco to inform the basic parameters of the simulation. They then simulated ride sharing MOD schemes under four different scenarios including simulating how well SAVs would work if they replaced a high-capacity rail line.
In the urban scenario, ride sharing was able to reduce vehicle miles traveled (VMT) by 11 percent and the fleet size by 29 percent at the cost of a 15 percent increase in total travel time.
In the rural case, a 28 percent fleet size reduction and a 12 percent reduction in vehicle miles traveled at the cost of a 3 percent increase in total travel time.
Efficiency gains due to ride sharing in mobility on demand are present but limited and may not be sufficient to compensate for the drawbacks of reduced convenience, loss of privacy, and higher total travel and drive time.