Potential Secondary Benefits

1. Improved social cohesion and understanding. Users of Air BnB report enjoying the experience of meeting people from other countries and backgrounds through bringing them into their homes. Briefly sharing the space of a car should have similar effects. People will be put in contact with others whom they would never meet under other circumstances. Granted, they may encounter awful people as well, but they also may meet a new business contact, golfing buddy, or future spouse. Women with safety concerns may want to limit their carpool choices to vehicles driven by women.

2. Furthering the goals of Vision Zero as well as the city’s goal of reducing its carbon footprint. By reducing congestion on city streets and the conditions that cause road rage, you would be making them safer for pedestrians and bikers. By reducing the number of single-occupancy vehicles, fossil fuel use is reduced. Just reducing the number of cars on Manhattan streets will reduce what traffic engineers refer to as “friction”, allowing traffic to flow better.

3. There would be no induced demand. Traffic flow improvements such as added lanes or larger interchanges typically cause what they call induced demand, where making a given traffic situation a little more bearable causes others to decide to use the same route, resulting in a condition where congestion is soon back where it was before the improvements. With this plan, the more people there are that carpool, the better it would work, and it does not rely on enlarging any streets, beyond the additional stacking space of the decks, to improve traffic flow. The economic incentive is to move more people with fewer cars. It also has built-in congestion pricing, in the form of surge pricing with Uber. The cars coming from the carpool queues would get priority in entering the tunnels, while those in the regular lanes would wait.

4. More time for personal pursuits. On average, the people who work in New York City spend a greater portion of their day commuting than those of any other major metropolitan area in the US. With reduced commuting times, people would be able to spend more time doing the things they enjoy, thus reducing their stress levels. Reduced stress translates into better health.