We propose a novel electromagnetic energy-harvesting device (EHD) for structural health monitoring systems of transportation infrastructures. The EHD is embedded in the road surface and uses the tread force of cars as the input force when tires of cars pass over it. Because the input force is very fast, the proposed EHD can generate a large amount of energy. The footprint of the device is 20 × 20 mm, its height is 7.5 mm, and its volume is 2.4 cm3. We measured the energy generated when a bicycle passed over the EHD 34 times at various speeds between 5 and 15 km/h. Subsequently, we obtained the regression curve from the results, which showed the relationship between the bicycle speed and generated energy, and estimated the electric energy generated by car at higher speeds. The results showed that, even though the size of the EHD was small, electric energies of 100 μJ, and 1.0 mJ could be generated at car speeds of 17 km/h, and 52 km/h, respectively.