Speed bumps are commonly used to control the traffic speed and to ensure the safety of pedestrians. This paper proposes a novel speed bump energy harvester (SBEH), which can generate large-scale electrical energy up to several hundred watts when the vehicle drives on it. A unique design of the motion mechanism allows the up-and-down pulse motion to drive the generator into unidirectional rotation, yielding time times more energy than the traditional design. Along with the validation of energy harvesting, this paper also addresses the advantages of this motion mechanism over the traditional design, using physical modeling and simulation. Up to 200 watts electrical peak power in one phase of three-phase generator during in-field test can be regenerated when a sedan passage car passes through the SBEH prototype at 2 km/h.