The announcement that Philadelphia will be rolling out its new bicycle sharing program this spring gives me a minute to reflect on the pros and cons of this new type of transportation infrastructure. First off, a bit about the program.
The program will be implemented in two phases. The first is this spring and will consist of 60 docking stations and 600 bikes. Riders can either get a membership or pay per use at the fully-automated station when they return the bike. The stations will be located in the heavier trafficked part of the city and the second phase is planned no earlier than 2017 and will involve 650 more bike and docking station placement in parts of the city that lack other transportation options . As far as cons go, I cannot think of many.
Though the cost for the first phase is over 14 million, planners anticipate being able to recoup that in the first two years . I thought safety might be an issue since there are going to be more bicycles on city streets, but the study by Fuller, et al (2013), found that in the Montreal bike share program there were no greater numbers of accidents or near misses  and that city has over 4,400 bikes in its system . I did find one definite con: people using a bike share were much more likely to ride without a helmet. In a study of the DC and Boston programs cited in Fishman, et al (2013), 80% of bike share riders were un-helmeted . This fact could be a little worrying, but if there are no fewer accidents …Then again, it only takes one to put someone in a comma. Maybe those running a bike share program could find a way to include helmets with the rental.
The pros of a bike share program on first thought appear to be numerous. Biking promotes a healthy lifestyle, bike shares offer transportation alternatives and greater convenience, the programs reveal that a city is trying to accommodate all of its citizens and that it is thinking green. This last one is important to me – the only form of transportation more environmentally friendly is walking. Well, that is at least what I initially thought. It turns out that it not clearly the case.
In a study on the cost effectiveness of 7 San Diego transportation policies intended to abate greenhouse gas (GHG) emissions, biking policies proved to have the highest cost per ton of GHG abated by far . In a study by the Fishman team (2014) of bike share programs in DC, Melbourne, London, and Minnesota, they found that vehicle miles traveled actually increased because of the balancing that had to be done to keep bikes from accumulating beyond docking capacity in some locations while other docking locations emptied out completely. Trucks hauled trailers carrying bikes from one docking station to another. The biggest problem with this practice was in London where few people used cars in the city anyway and where many people used the bikes to travel from the outskirts to the city’s center. Even for other cities in the study, it was found that bikes did not replace car trips as much as replace public transportation ridership or walking .
Though the Fishman study (2014) brings out some interesting points, London was an outlier and the study only looked at these four cities. A study about the Denver bike share program showed that between 22% and 66% of trips with the share bikes replaced vehicle trips . An interesting consideration that I did not see quantified in any of these studies was that the trips replaced were also the short ones that if a car was used would contribute greater GHG than average owing to the fact that cars burn gas inefficiently until they achieve operating temperature. Regardless, there are now at least 700 cities in the world that have a bike sharing program  and there is a whole lot more studying that can be done about these innovative transportation programs. For instance, do bike share programs increase the legitimacy of bicycle commuting and therefore encourage vehicle drivers to bike more even if they do not use the program? Does the presence of a highly visible bike share program increase the eco-consciousness of the public in other ways not related to transportation? There are a host of other questions that we could investigate and starting from the program’s inception in Philadelphia might be a good way to start.
 Brust, A. (April 25, 2014). Bike share not coming to Phila. till spring. Philadelphia Inquirer. Retrieved from: http://articles.philly.com/2014-04-25/news/49381541_1_bikes-and-stations-bike-share-system-bike-share.
 Fuller, D., Gauvin, L., Morency, P., Kestens, Y., & Drouin, L. (2013). The impact of implementing a public bicycle share program on the likelihood of collisions and near misses in Montreal, Canada. Preventive Medicine, 57(6), 920-924. doi:10.1016/j.ypmed.2013.05.028
 O’Brien, O., Cheshire, J., & Batty, M. (2014). Mining bicycle sharing data for generating insights into sustainable transport systems. Journal of Transport Geography, 34, 262-273. doi:10.1016/j.jtrangeo.2013.06.007
 Fishman, E., Washington, S., & Haworth, N. (2013). Bike share: A synthesis of the literature. Transport Reviews, 33(2), 148-165. doi:10.1080/01441647.2013.775612
 Silva-Send, N., Anders, S., & Narwold, A. (2013). Cost effectiveness comparison of certain transportation measures to mitigate greenhouse gas emissions in San Diego county, California. Energy Policy, 62, 1428-1433. doi:10.1016/j.enpol.2013.07.059
 Fishman, E., Washington, S., & Haworth, N. (2014). Bike share’s impact on car use: Evidence from the United States, Great Britain, and Australia. Transportation Research Part D-Transport and Environment, 31, 13-20. doi:10.1016/j.trd.2014.05.013
 Ramaswami, A., Bernard, M., Chavez, A., Hillman, T., Whitaker, M., Thomas, G., & Marshall, M. (2012). Quantifying carbon mitigation wedges in US cities: Near-term strategy analysis and critical review. Environmental Science & Technology, 46(7), 3629-3642. doi:10.1021/es203503a