why people are not harvesting energy through roads by using piezoelectric systems

even though in israel and us this type of roads are tested and said that roads can supply energy why people are not having a power plant by connecting it to piezoelectric which are under road and supply to people 

Cost ? Cost/benefit ?

In general, since there is no such thing as a free lunch, if you "extracted energy from roads", that energy would come from the rolling vehicles on it.

sujayr1 (author) 2 years ago

thanks for your answers

Free energy is not free.

Wind turbines; you buy or you build, you maintain, not free.

Solar cells; you buy or you build, you maintain, not free.

Hydro dam; you buy or you build, you maintain, not free.

Free energy is not free of cost, it may be free of pollutants while in use, (Doesn't include manufacturing) and low in environmental damages, but it is not free.

The type of generation system you describe would cost ten time more than a wind turbine. Just to do a repair the generating system; you would tear up the road, then you need to fix the road after repairing the generating system.