Its commonly known that grabbing a bike instead of hailing a taxi helps reduce greenhouse-gas emissions. Now multiply the change one bicycler can create by the population of a city. Montreals biking-sharing program, Bixi, has done just that and now plans to expand to Boston and London. A healthy and eco-friendly alternative to other modes of public transport, Bixi works similarly. In Montreal, a user heads to one of the 278 stations, pays a fee, rides the bike wherever he or she desires, then places it back in any one of the Bixi stations. Already claiming to have reduced greenhouse-gas emissions by more than 909,000 kg, Bixis expansion in Boston is projected to have 290 stations and offer 2,500 bikes for usage. Thats definitely smart transportation.