The piezoelectric energy generating roads have been proposed in the car capital of the world, California. The design is based on piezoelectricity that is produced in response to mechanical stress applied on some solid materials like crystals and some ceramics. The design proposes the placement of piezoelectric sensor beneath the road surface which would produce electricity from the vibration of caused by movement of vehicles on road. When applied on road, the piezoelectric technology could produce up to 44 megawatts of electricity per year from one kilometre stretch of the road and meet the energy demand of about 30,800 households.
The basic principle which we use to generate electricity is the piezoelectric effect. A piezoelectric material is that one which converts mechanical energy or vibration energy that is experienced on it, to a charge which can be stored. When a force or pressure is exerted on the elastic piezoelectric crystal material, the crystal gets deformed and this causes it to develop charge between them and the crystal goes back to its original state. This charge flow is converted to a voltage that can be stored in a battery. We explain about a disc shaped piezoelectric buffer plate in our paper. Since the power obtained from a few of them will be in a very small amount, we use voltage amplifying circuits here. As the size and number of piezoelectric crystals increase, the energy obtained from them also increases. street light is controlled automatically by Light Dependent Resistors (LDRs). With the help of LDRs the street lights are automatically switched off during day time and switched off during night time. The automatic traffic light control is made possible by two pair of IR transceivers placed on each road of the four-way junction. Each transceiver pairs are kept face to face width-wise on each road. When the IR signals between each of the transmitter and receiver pair gets cut proportionally according to the traffic density on each road, the traffic lights are controlled. This function with the help of a program stored in a microcontroller. Besides all these, the charging condition of the battery is sent and indicated every second to the nearest traffic control room.