Resumen
Many cities around the world have to deal with severe parking problems as the continuously increasing demand cannot be served by the existing supply. Research has showed that a high percentage of the overall traffic in cities derives from the parking place search causing additional traffic problems and time loss. The present work describes a field trial on detecting free parking places, using vehicles equipped with ultrasonic sensors. To validate the sensor results from those vehicles a manual measurement was undertaken in two German cities which will lead to a further improvement of the current system.