by Justin Tyndall and Lily Gordon Koven
May 2013 saw the arrival of Citi Bike in New York City. Although the uptake of Citi Bike has exceeded many people’s expectations, the challenge of managing such a large system in a high density city has proven difficult. Five months after the initial launch, Citi Bike boasted over 90,000 annual members and more than 9.5 million miles travelled on the bright blue bikes. Although its system of 6,000 bikes pales in comparison to others in dozens of European and Chinese cities, when it launched, Citi Bike became the largest bike share system in the Western Hemisphere. Citi Bike is one of over 400 bike share systems to launch in the last five years, marking a 700 percent growth in systems worldwide.
This explosive growth hasn’t been matched by a solution to the greatest challenge facing most bike shares: rebalancing, or the process of redistributing bikes between ‘attractive’ and ‘repulsive’ stations.
As with all transportation systems, bike share systems exist within diverse commuting, topographical, and geographic environments. As commuters ride into business districts in the morning, ‘repulsive’ stations empty out and leave few to no bikes. Conversely, ‘attractive’ stations in busy neighborhoods fill up, leaving no place for riders to dock their bikes.
According to a September poll of thousands of system users, 64 percent of Citi Bike riders are most concerned about finding an empty station when they want to ride a bike or a full station when they want to return a bike. These station outages, when an ‘attractive’ station is completely full or a ‘repulsive’ station is completely empty, mean riders wanting to return or borrow a bike have to travel to a nearby station, resulting in delays and frustrations.
Under contract with the City, NYC Bike Share faces financial penalties when multiple complete station outages occur for more than one hour. To avoid outages, dozens of rebalancing teams shuttle bikes between full and empty stations. Big box trucks that carry up to 60 bikes help restock large, busy stations like those around Penn Station. These trucks carry high volumes of bikes but have difficulty navigating narrower streets and cutting through city traffic.
Perhaps the most visible rebalancing vehicles to New Yorkers are the Citi Bike-branded white sprinter vehicles that carry 25 to 30 bikes. Sprinter vehicles can effectively maneuver smaller city streets more easily than rented big box trucks, but must also navigate city traffic. Sprinter vehicles can often be seen outside of the Puck Building, removing bikes after the morning rush hour.
The newest rebalancing vehicles are bike trailers, capable of attaching to Citi Bikes, and hauling three additional bicycles. The new trailer bikes, while only able to carry a few bikes at a time, can smoothly and quickly maneuver through traffic. In creating station pairs and shuttling bikes back and forth, Citi Bike is able to rebalance between residential and commercial neighborhoods. This small scale intervention takes advantage of the same reality that makes bike share popular to consumers: over short distances, cycling is almost always the quickest way to get between two points in the city.
Despite the varied forms of rebalancing, Citi Bike still struggles to meet demand for riders. Citi Bike recently opened three hubs near Penn Station, Pier 40, and Delancey Street where broken bikes can be repaired and working bikes can be staged for vehicle pickup in order to shorten the travel distances of rebalancing vehicles. The main Citi Bike warehouse is in Sunset Park. A rush hour trip from South Brooklyn to Midtown could take upwards of an hour and exceed the one-hour outage limit.
Citi Bike’s vehicular approach to rebalancing mirrors tactics used by other systems, including Paris’s Velib, Washington, DC’s Capital Bike
Share, and Chicago’s new Divvy Bikes. Beyond the use of vehicles, some other cities have been able to institute incentive structures that encourage riders to transfer bikes from overstocked to under supplied stations. In Paris, the Velib system offers riders fifteen free minutes of ride time in exchange for returning a bike to a designated V+ station, in outage prone areas. Annual members can store this credit for later while short- term members receive a discount on their ride.
In Washington, DC, Capital Bike Share introduced a rewards program to encourage rider rebalancing, offering a free yearlong membership to the rider who completes the most trips on particular ‘off-peak’ routes. Velib and Capital Bike Share have also used rider competitions in the hopes of sparking rebalancing activity; the success of these programs has not completely alleviated rebalancing woes.
While over half of users surveyed expressed frustration with bike distribution, officials at the City’s Department of Transportation believe commuters are tweaking their schedules and destinations to ensure easier access to bikes and docks during the morning and evening rushes. City officials and transportation experts also see the rebalancing struggle as a sign of the system’s success. If and when the system expands to include new business hubs and commuters with different travel habits, some of the demand challenges may begin to resolve themselves. In the meantime, mathematicians, programmers, and planners in New York City continue to experiment with new algorithms, models, and methods in an attempt to predict demand and balance the system. Fortunately for the planners of New York, many other jurisdictions have dealt with similar problems before, and there is a wealth of best practices to draw upon. Citi Bike has quickly become a visible and vital part of New York’s transportation infrastructure and by ensuring its dependability for all users the system will endure as an element of life in New York.
Sources:
US News. http://www.usnews.com/news/articles/2013/06/05/ the-exploding-growth-of-bikesharing
Streetsblog. http://www.streetsblog.org/2013/10/17/ta-poll- majority-of-citi-bike-users-want-protected-car-free-bike-lanes/
Velib. http://www.velib.paris.fr/Comment-ca-marche/Les- stations
Capital Bike Share. http://www.dc.gov/DC/DDOT/About+DDOT/ News+Room/Press+Releases/ci.Capital+Bikeshare+Launches +Summertime+Competition+to+Reward+Reverse+Riders.print