This research paper by Shreya Dave, Massachusetts Institute of Technology (MIT), was published in February 2010. It compares modes of transportation in terms of their environmental impact by conducting a complete life cycle assessment. According to this study, walking, conventional bicycling and electric bicycling are release exactly the same amount of greenhouse gas emissions. All forms of personal transport are at least three times better than any other form of commuter transport.

While an electric bicycle consumes more energy (both to produce and to operate) and releases the associated greenhouse gases, a conventional bicycle requires the operator to work harder and breathe more heavily. In effect, the impact of the electric bicycle is entirely negligible.
Ultimately, this study is relevant for understanding the impact of various types of commuter transport. Electric bicycling, conventional bicycling, and walking each have about the same impact when considering commuting to
work. Walking is the most energy intensive form of personal transport from the human's perspective but since most Americans consume ample calories, an increase in food intake was ignored. Accordingly, walking releases the most amount of carbon dioxide from breathing. Thus, while an electric bicycle consumes energy and releases emissions to manufacture and operate, the amount is the same order of magnitude as a humans breathing activities during a brisk walk. While the exact accuracy of any life-cycle assessment cannot be guaranteed, the overall impact and comparisons are very interesting to understand and consider when making individual choices.