Many studies show that carsharing reduces transportation costs for a large segment of the population. Carsharing also reduces the number of private vehicles on the road because carshare members do not purchase their own cars. However, the traditional carsharing business model is difficult to scale geographically to neighborhoods with lower population densities because the operator must bear the upfront fixed cost of purchasing or leasing the vehicles in the fleet. In contrast to traditional carsharing, peer-to-peer (P2P) carsharing allows car owners to convert their personal vehicles into shared cars that can be rented to other drivers on a short-term basis. This model helps to improve the situation in which most privately owned vehicles sit idle more than 90% of the day. P2P carsharing alleviates upfront costs and thus is more economically consistent with lower-density neighborhoods than is traditional carsharing. As a result, P2P carsharing provides greater potential for car accessibility than traditional carsharing does. Several new service companies are dedicated to P2P carsharing. A methodology was developed to assess the market feasibility of P2P carsharing. The methodology was applied to develop a case study of P2P carsharing in Pittsburgh, Pennsylvania. The market for P2P carsharing was found to be economically viable. However, uncertain and fragmented public policy and car insurance regimes threatened the growth and investment in P2P carsharing.