Generating energy from footfalls

Repost from Wired

British engineers are converting street vibrations into electricity and predict a working prototype by Christmas capable of powering facility lights in the busiest areas of a city.

"We can harvest between 5 to 7 watts of energy per footstep that is currently being wasted into the ground," says Claire Price, director of The Facility Architects, the British firm heading up the Pacesetters Project. "And a passing train can generate very useful energy to run signaling or to power lights."

Interesting idea , the drawback or the catch is how can this energy tapped and used when the source of energy is not continuous .
I had a similar idea while standing next to the Tel Aviv Jerusalem highway and almost being blown off my feet with passing vehicles . The suction that the vehicles moving at 100+ kmph is tremendous , by the way same as drafting when on a bicycle , so if one was to line the 60 km stretch between TA to Jerusalem we could surely produce enough energy to light up the highway .
Ps ; If I could figure out how to wire my kids to tap all the energy they expend , I would be a millionaire .