Pilot projects and real-world-experiments evaluate short periods. One example could be the temporary rededicaton of space or speed limits for a few weeks.
Field-tests (Reallabore) are long-term projects. Scientists stressed that in order to gain reliable results it is necessary to run them for at least three years, preferably seven to eight years. The planning should allow for long coordination processes, especially if the project is supposed to include a broad range of stakeholders or buttom-up decision-making-processes.